Maybe that's why he wanted to find a new accountant. 

Could some of the expenses allocated to his unit be considered a management expense -- he has to be onsite to make repairs, collect rent and call the cops when there are loud parties?  Isn't he really overpaying his taxes, if he is counting his own rent as income?  He's not deducting it elsewhere, is he?

'Oh what a tangled web we weave/When first we practice to deceive'