Word pronounciation

My son is 10 years old. Lately he's been having trouble pronouncing certain words. I notice that the s sound is often an sh and vice versa. For example he pronounced smaller shmaller. Sometimes if there's a r in the second syllable of the word, he will also put it in the beginning, such as frabric for fabric. He used to do it every so often when he was younger, but it's been a long time since I've heard him do it and now he's doing it more often. I know there is a lot that is related to the sensory system.

My son does have other sensory issues, most of which have improved as he's developed. He is particular about clothing and sometimes still has trouble getting dressed in the morning. It is usually when he is tired, stressed or a combination of both. He struggles with focus and organization at home and at school. I've noticed that he seems to need more sleep than other kids his age. Sometimes if I don't wake him up he'll sleep 12-13 hours a night.

He is very sweet, but frustrates easy and looses the ability to control his behavior when he's in this stressed out frustrated place. Not usually at school, but at home with me(his mom). I don't know if that's our dynamic, or just that he feels safe with me. He did OT when he was 7/8. I felt like it helped a little. Please let me know if you have any information on the word sounds and/or any suggestions.