Dear Ishu, it’s good to know the person before marriage. His mother must be saving the amount for future and rest of the amount must be used in monthly household expenses. The matter related to income of a man is very sensitive matter. If he is ready to take your responsibility then you need not worry. You yourself are also working. So I don’t think that there will be any problem regarding finances. You are financially independent so don’t bother much about the amount given by him to his mother. Money is secondary and understanding between both of you is primary. Don’t try to change him, if you are ready to accept him as it is then only proceed further. I don’t mean to accept bad habits as it is but what I mean is every person is different n thinks differently. However you can make him understand that investing in kitties is not safe n RD/FD is secure. Moreover you also need to understand his mother. Maybe she is saving for future. If really love him then don’t let finances come in between but if you don’t love him n you are looking at him like any other male as your future husband then you should not proceed further if you don’t like the proposition n the way he is leading his life.
Personally I think you should see as to how he is as a human being because rest of the things can be easily taken care of as you both will be working and after marriage you both will be we and not you n him.