Hi JMK!!! Is this one of the Seven Christmasses of Frances Farmer?
Hmmmmmmmm DRGEORGE - This is just my opinion. Your room mate is obligated to pay 40% of the rent, whatever it is. If your rent for some reason went up one month, would you pass the increase along to him, or would your own share increase? Then again, he has budgeted a certain amount for December..... Then again - if he pays a lesser amount, your gift from your sister is negated. It is a dilemma.
I think, the difference in the rent he pays and what he owes this month, is actually part of your sister's gift to you. I could see how it would make you uncomfortable, but if you think it would bother you, you could always donate the difference to one of the great seasonal charities - unless you are Ebenezer Scrooge.