Indiana State is Div 1 and as a result, he'd have to sit out a year if transferring. There might be clauses that I'm not aware of that would allow him to play immediately, but that used to be the main rule. I.E if ISU's coach would be let go. He might be able to transfer out without having to sit out.
Scholarships are likely all tapped out and he'd have to be a preferred walk-on or go to fall camp and be one of the players that earns the scholarship at the conclusion of fall camp. Coaches usually reserve a few to motivate the players to perform thru camp.
He should be communicating with coaches ASAP as he could transfer at break and might be elgible right away (coaches and AD would know those rules).
FYI, I'm linking Rob Ninkovich's retirement speech. It is worth hearing it in it's entirity as he tells part of his story that he was a JUCO and tried more than once to get Joe Tiller's attention and it took multiple attempts to get thru to Joe. I'll let him tell his story.
What I'm trying to say is that he might have to be very persistent to make it happen.