How he spends HIS money is his business. You were ALL responsible to pay a portion of the utility bills, weren't you? If he failed to pay his share, then the other roommates should have paid it , including you, and then you evict the bum. So, what happened? Knowing he was paying late on a regular basis, you should have made sure it was paid. Relying on him to pay his share and not checking that the bill was fully paid is irresponsible. You can sue him for your share but, regardless, how he spends HIS money is his business. All you need to worry about is that he did not pay his portion. Prove that you did and the other roommates and when he cannot prove that he paid his share, then you should win that part of the case. Of course, you should be more prepared than just showing that but, that's it at its most basic level. Focus on his not paying his share, not what he does and does not do with his money.
Certified Paralegal, with 25+ years' experience & with Landlord & Tenant law experience.