I doubt it's the kiddy locks... they still work normally from the outside, you just can't open them from the inside, like you said, Detrich. He must have tried to open them from the outside. I've had a door stick on me. Nothing that beating the $#!+ out of it with work boots from the inside couldn't fix.
(E34 525i... what else is wrong with it... or, maybe easier, what actually works on it?)