CaptainTycho has a point, how old is he? in my family there's a rule [goes way back] you don't date until you're 16. myself i had no problem with it, and i like that rule, i think you're too young and immature before that time. even though you can still make mistakes at 16, you're old enough to understand better than if you were 12, or 14.
anyway, off my soap box, talk to his mother, just be his friend, get to know her, then she might 'loosen her grip' as you put it. just don't be manipulative, good chance she'll see through it.
since you asked magickally if there's a solution, i would go for a spell to get his mother to like you more so she would let him date. but again, i don't recommend it at all, especially since i don't know how old he is, it's far more understandable not letting her 13 year old date over her 30 year old, but either way you're forcing your will on another, and no good comes from that.