you can use a lightweight interfacing (available in fusable-or sew in) to add (body and substance) to the existing fabric- will also add stability and durability to help it last another 37 years :)
my daughter still has the one i made in 1976- when it became (thread bare) i told her to just toss it out- i would make a new quilt---OH NO!!! she could not do that- so i used a fusable stablizer- pressed to the back of the fabrics and made that quilt into a new quilt- with new batting and backing- but the (same old front)
she loves it- and it turned out better than it was in 1976 :)