Re: Younger cat is acting strange towards his mother
Welcome and I'm sorry you are having trouble with your cats.
First, is the boy kitten neutered? If so, this could be the cause of his mating-behaviors. Even if he is neutered, he could still exhibit mating behaviors.
Second, is the female cat spayed? This could also play a part in the behaviors.
Finally, the mother cat was gone long enough that the two cats (mother/son) do NOT recognize each other as family. Both have probably forgotten the familiar smells of each other and they are like "strangers" now. You can do a search for "cat introductions" and see what kind of good information would be useful for you.
Welcome to the site,