I think most importantly you need to tell us whether you're living at home or not whilst studying at university. If you are, then there is a discussion to be had regarding what your mother should have as a reasonable expectation of 'board'. If, however, you're living away from home, then the answer is simple - your mother has no right to expect any sort of money from your student funding (the clue's in the name 'student funding') and you should absolutely not feel bad for taking this course of action. In fact, it is you who should be asking her for money, though I understand and respect that you don't because of her financial predicament.