How often does your boyfriend's mom let him out of his crate each day? I'm no "expert" on potty training pups by ANY stretch but.....since he's still not housebroken, I would think he needs to be let out quite a bit more than he may be right now. Have you tried to train him on pee pads? When we got Gage, he was such a scared little puppy (I rescued him from an abusive home - the idiot gave him to me cause Gage kept peeing in the house - he didn't even try to housebreak him!). I bought some pee pads for accidents and now almost 3 years later, he will only go on the pee pads. He will tinkle outside but #2 is left for his pee pad - he's very proud of his pads
Chin up - sometimes it just takes longer and a great deal more patience. Just keep working with him - and maybe check into an X-pen. Gives him more freedom of movement (he's confined in his crate a good deal from what I gather in your post). Put a pee pad on one side of the x-pen and his crate on the other so he can get in and out to sleep. See if that helps any.
Best of luck!