Without actually checking the phone, it's just guesswork, but you could have broken a pin on one of the connectors, broken a wire inside one or even blown a driver on the motherboard.
It's too late now, but I always warn people who are thinking about opening their phones to repair them that it's cheaper to pay a shop to do the repair, than to pay the shop to figure out what you broke, fix that, then do the original repair. Which is probably what you're (or your friend) going to have to do.