male cats fighting!!!

i have a male cat. he is outside. there has been a family moved into the home three doors down. they brought a big ugly orange and white tabby. he often fights with my cat. i often hear screams and he chases him all the time. i am scared for my cat. will he die? there is also a female stray.could they be fighting over her? what can i do to make this stop? my dad thretends(sp?) to buy a gun and kill the tabby. :( i know he will. what can i do to make this stop? i have talked to the people over and over. they just say "hope your cat lives" that's not nice. i even told them of my father's plans. they said " they will just get two more cats"

HELP!!!!:(

Maybe you should leash train your pet and stay outside with him when he has his outside time. Are there laws in your area about stray cats? It sounds like he isn't neutered. Is your cat neutered? I hope everything works out!

yes he is fixed. i just got him fixed two weeks ago. he is a full outside cat. i cannot bring him inside because of my parents allergies. between my post and now i had to go chase off the cat agian. i am very worried.:(