Tell David he can get his groceries down below $400 a month. He can save even more by looking up local churches that will provide food with no questions asked.
Tell David to stop pirating stuff. He can watch stuff on YouTube or network sites like everyone else. No need to stoop to the level of theft.
Otherwise, good for David. And for $900 a month - with neighbors like that, he should turn them into characters in a novel. Pass his time by investing in a writing future. :)