Male cat 'being bad' because of kittens?

The spraying is his way of marking his territory. Locking him in the bathroom will not help. In fact, it my hurt because he'll associate the punishment with the kittens. For now I would keep him and the kittens in separate rooms. Also, any area that he's sprayed needs to be cleaned with an enzyme specifically for cat urine. This can be found in any pet store. If not properly cleaned, he and any other cat will smell the urine and keep going in that area. Finally, pay some special attention to him. When we have foster kittens, I make sure there is special time every day where the kittens are locked in their room and my cats get their own play/cuddle time.

The problem is that he's now a sexually mature male, and this is what they do. They spray. He's marking his territory and doing what Nature is compelling him to do. The attention seeking behavior is because of the kittens (he couldn't care less that he's the father - cats don't have the same concept of 'family' that we humans do - he is the 'baby daddy' not the 'father'). The spraying is because he needs to be neutered. He's going to become increasingly more aggressive, and obsessed with going out to find more females to mate with. The spraying will escalate until your house reeks of it. Call the vet first thing Monday morning, and get him the first neuter appointment that they have available.

Yes when a new animal comes into the household male cats will be "threatened" so they will do these things to be the alpha male. Just put him outside when he does something "bad" He will eventually stop when he gets used to the kittens.

Jealous.

Yep, any sudden behavior changes are directly related to the kittens.

Neutering him may help, it may not.

He may come to accept the kittens, he may not.

He has no concept that they are "his" kittens. He doesn't care. They are intruders and therefore the enemy!