I think a serious confrontation is needed. I agree that letters are rather passive-aggressive and won't be taken very well.

The thing is you need to confront him in a calm manner -- no anger, no frustration, no accusation, no blame. Make a chore list and with clear instructions on who is responsible for what on which day. If someone does not do the required chore they will have to make a small cash contribution to the 'house fund' (or whatever), that will go towards paying for maintenance and grocery. It might be a good idea that everyone buys their own food -- designate spaces in the fridge for each person. If you make a mess of your room to the point that it becomes unbearable for other people in the house, again, you pay a 'penalty', and it actually goes to the one that has to clean your room.

Easiest way, though, is to kick him out and get someone new.