My cats are being weird?

so my cats are brothers, their both also gay and hump each other. they rarely fight (when they do fight they just hiss and swat maybe once or twice) one of my cats is kind of cripple i guess? he cant bend his back legs when he walks, he's really stiff he has never attacked anyone or anything not even his brother (their both house cats the older ones mine the younger ones my moms and mine really doesn't swat or hiss) hes kind of old i got him when i was 7 im now 15 i don't remember when i got his brother (same mom, same dad) but hes younger not by much though (hes acts like the 'alfa male') i was laying in my bed around 30 minutes ago i was sleeping and i heard a noise it sound like a loud scream that came from my moms cat, i got up to check he had his ears back stand over my cat who also had his ears back my cat looked terrified, my moms cat started making weird noises like he was talking? my cat just stay in a squat position but looking up at his brother. all of a sudden my moms cat pounced on his brother and viciously attacked him (he's NEVER done this before, even to other cats we brought over) he was hissing weirdly, biting, scratching i was scared my mom started crying so we got the broom and tried separating them then my moms cat started attacking my legs (which hes NEVER also done before, him or my cat has never ever scratched me once in my life) i didn't wanna kick him but i was crying so i grabbed him by the skin on the back of his neck (which was hard because his coat is thick and hes heavy) but i put him in the bathroom once i dropped him he was hissing like crazy and tried getting at me again, i shut the door hes been stretching at it and screaming since. i checked my cat his eyes were all teary it looked like he was gonna cry and he was bleeding on his neck. now he keeps walking toward the bathroom door and meowing gently and when he meows the other cat gets louder and tries digging through the door even more? help? my mom said my cat wasn't doing anything, her cat just came over out of no where and started growling my cat didn't even growl back so im confused?