Tell your nephew you will make him a quilt if he will buy the fabric for it, also tell him if he'll buy the fabric for the quilts to sell then you will give him 10% of the profit. That may change his mind.
I am also disabled and cannot hold down a public job. I have to be able to sit when I need to or stand when I need to. I had some scraps that I accumulated a little at a time through the years. I'm sewn clothes all my life and when I would have left over from making clothing I would keep them. Also when I worked at sewing factories when they would have scrap sales I would pick up scraps really cheap. I finely had enough to make a log cabin lap quilt. That got me hooked.
My DIL brought me a bunch of fabric she bought at a yard sale. She gave 10.00 for all she could fit in the back of her SUV. Then I've been picking up some at the Goodwill. I can usually get a bundle for anywhere from 2.99 to 4.99. I also heard a woman advertize on a radio program the call the Swap Shop that she had some quilt scraps she needed to get rid of. I called her and made arrangement to get them. She said she had advertized every day for a week and no one wanted them.
I have made 3 large quilts for my grown kids for Christmas and 3 lap sized for my 3 grown granddaughters for Christmas. I think in all for those 6 quilts I made I only bought enough fabric for 2 backs and one top. The rest was freebie.
So NO do not give up on something you enjoy. You just have to be clever in finding ways to afford what you need.