My boyfriends kitten has worms. and something else??? ?

OK so my boyfriend found a kitten in a different town about 3 monthes ago, brought it to his moms house, which she has another cat as well. very clean nice house, other cat is very clean. she brought the kitten to the vets to get it dewormed and all its shots, all were waitin for next is for it to be old enough to get declawed and fixed. ok so anyways, ever since the day he brought this kitten to his moms house, its been farting non stop, like literally every half hour it farts, and the fart knocks out the whole room!!!!!! its soooo gross, it smells like eggs. and he goes poop every half hour as well, so she told my boyfriend he has to move in to our apartment!!!!!!!!!! sooo hes been such a pleasure living with us, other than the farting...but NOW i look at his , and little worms are coming out. WHATS WRONG WITH THIS CAT!?!? i feel so bad for it. i kno his mothers cat didnt have worms because they both got dewormed...and hes still as stinky as ever. we havnt brought him to the vets yet b.c we just moved into our apartment and havnt had enough money yet, but we're almost there, does anybody have any ideas on whats wrong with him!? other than the worms part. THANKS!!!!