My DS1 also did not like blankets at all. We usually dressed him in warmer clothes for night and luckily in our condo, there are separate heat controls in the bedrooms, so I can adjust the heat in his room over night. I tried once to put a heavier blanket on his bed, but no go. Then I found an old knitted lightweight blanket that a friend had made for him as a baby, and that one he tolerated.
. So you could maybe experiment with different weights of blankets? I like the idea of having him help pick out the blanket for his new bed. I also tried incorporating a blanket into our play time to get him more interested in it. You could put it out in the floor to sit on, take it to a couch or chair to snuggle with/read books with, etc. Then maybe he would become more attached to it?