Hi BeatingHeart,
he recently was laid off.
I suspect that this may be at the root of the problem. Particularly, if his 'bad' behaviour is only a recent phenomenon.
If this is the case, then I suggest that you get a lit bit sneaky in order to help both of you resolve this issue. I suggest that you get some money into his pocket at least a week before your birthday, without him knowing that it has come from you (via one of his good friends or family members), preferably as a gift, rather than a loan.
Don't expect him to spend all of the money that you get into his pocket of your birthday present.
Most importantly, regardless of what he gets you, go out of your way to reward him, by showing your appreciation and happiness.
"What gets rewarded, gets done."
If you think that it is indeed his recent job-loss that is adversely effecting his behaviour, and he is normally a good chap, then try to be forgiving, and help him get back on his feet.
Best wishes,
John