Ghosts?

Hi parents, I have a 4 year old, level 3 ASD non verbal boy. He loves his room and his books, it is his safe space and he will happily spend all day in there reading and looking at pictures laughing etc.

As of yesterday evening when it came to bed time (which he loves and has always been a great sleeper) he refused to enter his room at all screaming and looking towards the corner and even after trying to calm him down he would not even enter his room, after re calming him down he went to sleep in our bed peacefully and easily. This morning once again he walked past his room when he woke up and again looked in his room towards that corner, let out a little whimper and walked straight past his room and will not enter at all even to get a book or if I try to hand lead him in there.

I am located Sydney NSW Australia, is there anything I can do to sense a ghost or find out what is going on or someone I can bring to the house to suss it out? Any advice is greatly appreciated.