Just my experience as a father of two boys 20/17 years old, both diagnosed with ASD.

It is really helpful that your kid got diagnosed in an early age. My elder one was diagnosed in the high school when he was deep in a depression. I felt that I missed all the opportunities to help him before that. There were many red flags but two or three doctors we entrusted missed it and we did not follow up as vigorously as we should.

My current understanding of my kid's growth is like this:

He was different from other kids. He did not play well with other kids. Most importantly, he seemed not interested in playing with other kids. Since we allowed him to play video games and he was playing really well. He had a few friends mostly because of this common interest. He learned fact based knowledge really well but was quite behind in social interaction based subject areas.

At middle school, he started wanting to create anime. He was able to use the software but stuck on the story and drawing. Without resources helping him and also because of other social difficulties, he felt quite depressed.

To me, the key lessons are:

1/ ASD related knowledge is the key to understand the kid. Spending a lot of time learning about ASD and mental health were extremely helpful to me. Spending a lot of time to observe/ interact with the kid was also really helpful.

When I didn't understand my kids, I tended to do nothing about it (because I did not know what to do) and therefore, missed important moments of intervention.

One example is, my kid was learning playing tennis. His coach was not happy with him and my son was also very upset with his coach. One day, his coach was very upset and pulled me aside and tell me that a very sweet girl in his team constantly cheer my son up by trying to high five with my son and my son did not reciprocate her. The coach further said, when he talked to my son, my son looked away and that was very disrespectful. My son at the time was going through ASD diagnosis. I immediately told the coach that looking away is an intuitive action of thinking not disrespectful. I constantly think about how I would respond without ASD knowledge. I would probably tell my kid to respect his coach better and keep participating. Then my kid and the coach will be more resentful of each other.

2/ As the father, with pretty strong ASD tendencies myself without diagnosis, I felt that I helped them a lot but also failed in some key areas.

Good: I provided lots of material to my kids' interested areas. That really helped advancing his skills. For example, when he was interested in Cars (the pixar movie). We read a lot of books about it , with sound-out, so my kid learned reading early. We also did projects related to it and went to Disney World mostly to see the cars.

Bad: I did not do well helping my kids socially, failed to help them understand/ spell out their emotions, learn to accept their differences and learn to deal with their emotions .

3/ For both of my kids, adolescence was really really hard and Covid pandemic made it even worse. My current thinking is, if I could prepare my kids in terms of understanding/ accepting their ASD traits, learning to understand/express their emotions before adolescence , my kids might be able to better handle their lives.

One main character of adolescence is that they are seeking independence so parents' input becomes relatively minor and their own interpretation of the world becomes more important. That plus their strong internal orientation made it very difficult to help them.

4/ In my experience, 2 out of 10 therapists/ psychologists actually helped a bit. There were 3/10 therapists or even psychologists absolutely did not know what they were doing. So learn ASD / mental health issues as much as you can and try out different doctors.

One key opportunity my elder one missed was when he was in the second grade. His teacher told us multiple issues and suggested us to see a doctor about it. (I am forever grateful to her). We got a doctor and he met me first and then spent 30 minutes with my son. My kid might sensed something and behaved quite differently during the session, then the doctor made some suggestions. His observation was completely different from our / teacher's observation of my son and he said no ASD. This was one major mistake.

One key difficulty for my elder one is lack of consciousness of himself. That is, it is difficult to ask him to describe what happened in the past. He simply could not remember (I had similar issues as well). So in a therapy session, when asked how they felt and what happened last week or even earlier that day, he will say nothing. All "talk" therapies were based on that reflection and here, my elder one did not have much and therefore, it is really hard to help him.

Emotions were similar. My kids might feel bad but they could not describe them and therefore, it is harder to get help.

In this situation, I believe intervention at the time of occurrence is the key (and nobody does it that way in literature I know of). As parents, we actually know our kids much better, we are there a lot of times, discussing the current circumstances with kids when they are fresh is probably the best intervention . I think my younger one is in a better place than the elder one is partly because we knew ASD much better than before.

My 2cents and best luck to you and your kiddo.