Most Helpful Guy
He's gonna offer, and he will insist, but it's nice when the girl tries to pay, or at least offers to split the cost, it just shows that she's not just for the money.
So offer to pay, don't mention his situation, just offer to pay, insist one or two times, and if he keeps insisting let him pay, it's his decision.
If he pays, tell him you'll pay next time. If you guys keep going on dates, either split the cost, or one time you pay, next time he pays.
Most Helpful Girl
Simply say that since you asked him out, you feel that you're obligated to pay. Some men though do have this "pride" thing where they feel emasculated if a woman does something for him that he can not do himself. It makes some of them feel like less than a man.
I'm hoping he's not like that.