Is it normal for a guy to give constant attention to another guy that he only know for about 1 month?

There's this new guy in school and he seems to be interested in me but I don't know about his sexuality. He would place his arm over me everytime we see each other and he only does this to me. He would also place his hand on my head and touch my hair or scratch my scalp at very random moments. He also likes to tease me a lot so much so that others started to say he's my big brother. Even if both of us are in a group, he would talk about topics that is somehow reIated to me. It is normal for straight guys to act this way or is he interested in me?