Hello there! The best options would be these of the following:
--- He seems to be in a world of his own.
--- He constantly rocks back and forth.
--- His mother communicates with him using gestures.
These are all common signs of autism. The other options, He is extremely good at drawing & He is very affectionate are things that can show up in people with or without autism, and aren't signs of autism.
I hope this helps and have a great rest of your day!
