C.L.
I agree with the plastic on the windows. We had a window in our bedroom that was broken and that really helped during the winter. (we got new windows this spring though yay!) Also, I don't know how old your son is but maybe he'd wear feetie jammies? It might not bother him as much as socks. I got my daughter fleece feetie jammies because she also won't keep a blanket on. I am hoping with her new big girl bed we're getting today that if I tuck the comforter/sheets into the bottom of the bed she'll keep them on. Good luck!