I don't have any information regarding resources, as such - although it seems that Artyczar will soon be able to help you in that respect. However, I have for some time been following a gentleman on YouTube who is having to deal with failing eyesight. He goes by the name of OldBlindDoug and this is his channel https://www.youtube.com/channel/UCeI...TCw3Kh94fhF6nQ
At the moment his channel includes both art and 'outdoor life/camping' videos, but he's in the process of separating these aspects and making his main channel just painting videos. Your friend might find Doug's discussions of how he copes with failing eyesight of some use - although I don't know whether his eyesight problem is identical to Doug's. Anyway, thought I'd post just in case it helps. Best wishes to your friend, Brian.