What’s in his mind? 😔

Earlier on I posted about my 3.5yo son having fear about kids his age or younger, his sensitivity towards musical toys, car horns & kids crying & screams (which is what turn him off from playing with younger kids). Besides that, he’s fear of strangers or people he met like once in a blue mood. For example, bcoz grandma babysit him since baby till now, so if there are people at grandma’s house reaching there ahead of him, he will refuse to go inside the house, and it’s either the guest leave or he leave, or else he will keep crying begging to go. But at school or at other places, he’s ok, not rejecting people and he’s ok with different environment. So it gives me a feeling like it’s bcoz his comfort zone is “being attack” that’s the reason he’s so upset? Coz normally it’s just grandma & grandpa at home, all the sudden some one else turn up, he’s very upset.