I hope they bring him back to Family Guy if this show gets cancelled. Cleveland will always be an important part to Family Guy. Family Guy is where he belongs.
I don't doubt the Browns would move back to Quahog based on Mike Henry still being credited as part of the main cast of Family Guy. Sure, Consuela, Bruce & Herbert still appear but usually only brief cameos, (one a month this season if I recall) but he's not doing a permanent character any longer.
Since (contractually I presume) he's still able to have that much on-screen credit when his presence on the show is much less since 2009, it would certainly suggest they'd simply bring Cleveland back. Provided of course Mike still wanted to do Cleveland after the show gets cancelled, which I can't imagine he wouldn't, but one can't say.