I'm in my second year at Navy in Tark.  For the first time ever I've recruited a player that's ineligible.  Luckily he showed up at my school.  I understand he will sit out the first season, but am I correct in thinking that he will not gain any ratings boosts since he is not allowed to practice?  I also read somewhere that he must maintain a 2.7 GPA or higher to qualify for a 4th year of eligibility.  If he can't practice and wont imrpove in ratings, does that just mean I should pump a bunch of minutes into his SH?

Yes you are right he won't improve at all this season. Yes put all his minutes in study hall, he will most likely end up with above a 3.0 for this season. 

Exactly, put every single minute into study hall.  He's not allowed to practice with the team anyhow.