Maybe you could try being gone MORE over the next couple of weeks, and ask your mom to try to become your cat's new best friend -- lots and lots of attention. Sort of wean him from the need to be with you and give him someone else to attach to.
Don't know if it would work, but it's an idea...
I could use some help teaching my wonderful new cat, Cory, how to play. I think he must've been owned by a wonderfully affectionate person before he became a stray. He's a total lovebug but has absolutely NO IDEA how to play!
He's around 5 y/o -- way too young to be a couch potato only...
