I'd wash it myself, not with synthrapol, but with Color Catchers. That way, you can see for yourself if the fabrics are still shedding dye and base your decision on that information.
That said, if it's still running, I'd recommend Color Catchers to whomever will be washing the quilt. Synthrapol is much more complicated to use properly than most non-quilters want to deal with when washing a quilt. I'd also put the care instructions on a separate quilt label for when the son goes off on his own.