Rozied, I think about writing to my AS also. It does take a lot of thought. Remember you don't have to do it today, you can add and subtract, until you feel comfortable with the letter you are sending. I know you feel he is a part of his nanas increased health problems, but I'm not sure you should write and particularly blame him. Just let him know her health is getting worse, and its best not to be demanding of her, nor bring any added stress to her. She is elderly.
Let him know your feelings about sending money, whether you choose to or not.
Huggs,
NH7