Text notifications

My son is not receiving text notifications from me. He has a iphone XR. I have a samsung note 10 plus. He receives the messages but doesn't get notification. The messages show read when he hasn't read them. This only happens with my number he receives messages from other non iphone contacts. He just got this phone a week ago. The previous phone he had broke and started doing the same thing. My number is not blocked and does not show do not disturb. Notification is set to default. I had him delete my contact info and re add it. He is still having the issue. Any suggestions?