HELP! My dad went and got 2 male cats about 3 days ago. They were fine, playing etc, I seen that one of them kept diareha, but I thought it would be fine, today it was fine, then about 30 minutes I go outside and he is not moving won't respond when we call him, and is vomiting, what is wrong?

He needs to see a vet. He is sick and will die without proper care, if it's not too late already.

?Oops! You must spread some Reputation around before giving it to odinn7 again.

Totally agree, your kitten needs to see the vet sooner rather than later.

It could be any number of things, many of them potentially fatal. You HAVE to take your cat to a vet. Better yet, take both. It may be contagious, and the second cat just doesn't have symptoms, yet. Even if it's too late to save one, you may be able to save the other.

Did your dad try to deworm them ? And exactly how old are the two?

Yes, I agree. To the vet !