As others have said, if schools showed interest and haven't offered yet, you're probably better off looking elsewhere, unless there has still be some very recent contact. There are opportunities for D1, but you'll have to do some legwork.
What are your son's measurables? Ht, Wt, 60, Position, Velocity, Etc? I will compare it to guys at my son's mid-major D1 and tell you where he would fit in compared to the guys they have there.