Is it normal he does these imo weird things?

From what I've noticed, ever since my brother(13)'s gotten to middle school, he's been developing all kinds of weird traits;mainly Germophobic, Anger, and Incestual.

Germophobic- He's developed a habit of keeping a separate shampoo bottle in his room, even though the exact same brand and scent's already in the bathroom. He also, according to our little sister(8), has to look at a clock to know when to get out of the shower before he starts to prune.

Anger/Incestual- He's real protective over our sister to the point where she can hang out only with him(Even if she wants to chill with me), and if she refuses, he threatens her with pics he took on his laptop of our sister eating in her room(Mom forbids her from doing so after one incident).

He also tends to go on a "rampage", stomping around the house and messing up her room, lifting up her mattress and placing it against the wall like he real strong. On terms of Incestual, he lets our sister go inside the bathroom when he's using it(Shower or otherwise), and our sister occasionally tells me(When she can chill with me after a fight the two of them had) he goes on sites like Chaturbate and essentially watches porn with her.