Before I forget or lose my mind typing on a tiny screen, some kind of bickering-like-siblings roommate situation? He's still stuck on his best friend moving out so he's sensitive about that space and probably irrational about everything. Him living with a girl might stir up some other things on the drama side, but i think if she gets business-minded with him about performing and music, they could butt heads (more room for drama) until she eventually helps him break out of his insecure shell and maybe develop an almost familial type of bond?