Icee,
I would get it back and tie it some more. My first quilt was a 100" flaming star (pieces were 20+ inches large). I did as you indicated - tying about 12" apart with embroidery/ crewel thread. I used old 100% cotton thread - material was a cotton/poly blend. My grandma helped me tie it.
After the first wash, seams started popping. There just wasn't enough support for the weight of the quilt. Because Grandma is long gone, I haven't wanted to take it apart and put it back together the right way, but I've never really been able to use the quilt because of all the broken seams. That was 40+ years ago!
Since it sounds like you have gifted the quilt, it's really better to just admit the problem before the quilt starts to fall apart, get it back, and fix it now while you still have the energy and desire to do so.
Good luck!