Hello Rania, thank you so much for contacting us. Certainly your first step would be to see your GP for referral to a Community Paediatrician, who would be able to complete an assessment for autism and look at your son's wider skills. Speech and Language Therapists can work with your child with or without a diagnosis. The Therapy would be tailored to your child's strengths and needs and is not 'one size fits all,' but would likely begin by developing his good understanding and working on ways for him to communicate, for example by starting with offering him two choices from objects, like yoghurt or banana. We also work with parents to identify individual strategies to support his communication. It sounds like he is using some lovely non-verbal communication already, such as smiling, eye contact and shouting.
It is very common for potty training to be challenging in children with delays or possible autism spectrum disorders. There are different reasons why this might be, but your Health Visitor would be your first port of call for this. They should be able to do some home visits. If he's not quite ready, they might suggest waiting, but using some visuals such as a picture of a toilet/potty and taking him on a set schedule.
Nicola Read, Speech & Language Therapist, The Owl Centre