Here's my attempt. I've taken Red Vipers terrific efforts and adapted it, mainly changing 'I' to 'we' as I think it's more powerful and adding detail about children etc. many thanks for the structure, I wouldn't have known where to start!

I hope others will do the same to mine if they think it's any good, which of course it may not be. But I totally agree that The more of us contribute the better imho. I've never really written anything like this before and it's entirely possible it's rubbish. It's also even more possible that my 'facts' are mixed up and may need changes going about, this has taken it out of me and it may need a lot of correction if anyone would like to do it. My grammar etc. may also be poor, I've proofread but don't always spot things when tired.
"Dear Mr Cook,
We are sure the recent public announcement that you made regarding how you will be giving away your fortune has already solicited numerous responses, some more deserving than others. However, on behalf of the hundreds of thousands of patients all across the world, of all ages, economic and cultural backgrounds suffering from ME/CFS/SEID (ME, hereafter for brevity), we feel it's necessary to highlight the plight of patients suffering with ME; and how partnering with your charitable organizations would directly save the lives of so many devastatingly ill patients all across the world.
This is a disease on the precipice of change for the better, however in order for this change to occur patients and researchers alike require funds to provide structure in order to drive research forwards moving into the future. We are asking you to be a driving force in that change, to drive forward hope for the future for a global patient group with a devastating neurological disease by taking an interest. We have the world class scientists, such as Ian Lipkin, poised for action, we have the patients willing to take part and we are beginning to understand the pathways we need to tread in order to carve a brighter future. What we lack is the finance to make it happen and to end the suffering for the hundreds thousands of men, women and children around the globe. We ask for you to help us make that happen.
We are uncertain if you have any awareness of ME, so we beg your indulgence while we take a minute to explain how this debilitating, often lifelong, disease affects men, women and children.
This neurological disease involves a multitude of systemic and often serious symptoms, which can affect all processes in the body, including cognition, digestion, physical function and many more. In many ways it can often be very similar to MS. Sufferers are typically left seriously disabled, often permanently. At its severest end it can kill. Such patients beforehand often spend years, and even decades, trapped without hope of recovery or sometimes even understanding, while they suffer neglect or even abuse because they have the misfortune to suffer from a neurological disease which isn't currently widely understood beyond a few specialists in the disease. Very severe ME can render patients, including children, trapped in darkened rooms, struggling to tolerate even minor stimulus such as sunlight or the lightest of noise, and reliant on being tube fed and round the clock care, sometimes for years on end. Even in its mildest form ME often renders individuals significantly restricted in terms of their quality of life and ability to function.
The onset of the disease is usually random, at the moment unpredictable, and typically triggers following a viral illness; or some other traumatic shock to the individuals body such as surgery or an accident. This initial onset is followed for the majority of patients by years of endless suffering. It is worth noting again that the disease can strike anyone, regardless of their age, gender, or global location. There are thousands of children who suffer with this disease all over the world, it is listed in various sources as the number one cause of school absence in children, meaning this disease not only strips children of their health, but also their opportunity for educational and social development alongside their peers. While prognosis is often listed as being better for children and adolescents, many of those have to learn to significantly reduce their quality of life if they wish to recover or regain greater function as they move into adulthood; raising the question as to whether they are truly recovered at all. For adults the prognosis for recovery is significantly reduced still further, a large number of patients are left without any hope of recovery at all and are faced with the prospect of spending the rest of their lives with significant disability, pain and all other symptoms.
Those of us who have composed this letter to send to you come from many backgrounds ourselves. From a 26 year old man who at the time of onset was working for the federal government before being stuck down and rendered bedridden within four weeks of onset. To a 28 year old woman who was initially struck with this disease aged seven and who totally collapsed aged 13, and who has needed constant nursing and care since then, with no real hope of recovery fourteen years on. There are many more voices locked in the shadows besides, there are thousands more stories to tell. Each has their own imploring tale which could be told in support. But collectively we have one voice, one desire, we are in desperate need of help to get a structure in place to fund research which, while often very hopeful of providing a cure and understanding of the disease, run into dead ends due to lack of funds. We are in desperate need of providing a long term structure to carry this hopeful progress further.
You would think such a debilitating disease would receive significant funding from governments, but in 2014 the National Institutes of Health (NIH) awarded $6 million in funding for ME and $14 million in funding for male pattern baldness. This is a story which is repeated globally, with research ready to go but lacking the financial resources to do it, as governments rank the disease lower in priority than things such as this. This is just one of the insurmountable hurdles that our community is currently facing, as a current lack of diagnostic testing has allowed certain interest groups to discredit the suffering of ME patients, despite decades of undeniable evidence to the contrary. Much like how patients with MS used to be historically be treated before research progressed to a greater understanding.
It is currently a critical time for ME research, as we have just had a promising study released by a team of Scientists at Columbia University's Mailman School of Public Health that identified a unique pattern of immune molecules in the cerebrospinal fluid of people with myalgic encephalomyelitis. In addition to a variety of other ongoing ME studies that desperately require funding, the recent breakthrough by the team of Columbia scientists could potentially lead to a treatment option for ME within the next few years. However, in order for such a breakthrough to be achieved, pioneers like Dr. Ian Lipkin and Dr. Mady Hornig desperately require additional funding to achieve these objectives.
You recently mentioned that you wanted to "plan to take time to develop a systematic approach to philanthropy, rather than simply writing cheques" and We commend you on taking such a calculated approach. It is for this reason, and so many more, that our community desperately reaches out requests your help. We ask you to be the driving force for change in this area, to help us to provide a structure for future research in order to drive forward hope of treatment, increased quality of life and even, eventually, recovery for hundred of thousands of men, women and children around the globe.
We thank you for reading this letter, And we thank you for your time and your consideration,
Signed, the ME/CFS/SEID community."