Well fix it, put a triangular gusset in
there welded to the frame and to the
rear body support, and do both sides
while you are at it, should be good as,
err well, better than new.
I had a rear body mount crack, about
8 years ago, maybe more, I welded it,
not extra reinforcement, just a weld, and
it's been fine for years, this was not a broken
weld, it was it the middle of the mount where
the body bolt goes thru
Good Luck
Wild