Definitely keep him in the mix by exposing him to sensible peer activities. Playing alongside other children his age is all that would be expected at his age - in other words, the amount of actual interaction that occurs is not very important. The apparent threat that he experiences with younger children will abate over time. Also, be casual and at the minimalist end re: reassurance. You want to avoid the kind of scenario when his upset becomes the vehicle for comforting interactions between him and you. When possible, but don't go out of your way to do this, limit his exposure to younger children to one or two children at a time so that he's not overwhelmed.
Thank you so much for your comment. In public places like restaurants or music class, or at gatherings with relatives where there are other small children, do you recommend removing him from the situation when he becomes hysterical or does this kind of "reward" the behavior? We can't think of anything else to do, since he starts crying as soon as he hears any young child say anything (in other words, almost immediately every time) and just doesn't seem to be able to regain control. We hate to be so disruptive to everyone else, and it doesn't seem like it helps him much to stay.
Chiefly due to the disruption the behavior causes for others, I would remove him. But when it's possible, such as at home with only a few people, it might be better to let him cope with the situation by sticking with it. When he has to be removed, you can let him know that he can return when he's calm and not crying. So, it's not the crying per se that's focused on, but the disruption that the crying promotes.
Oh, good! That's actually a tactic we've started lately. Thanks once again.
Chiefly due to the disruption the behavior causes for others, I would remove him. But when it's possible, such as at home with only a few people, it might be better to let him cope with the situation by sticking with it. When he has to be removed, you can let him know that he can return when he's calm and not crying. So, it's not the crying per se that's focused on, but the disruption that the crying promotes.
Chiefly due to the disruption the behavior causes for others, I would remove him. But when it's possible, such as at home with only a few people, it might be better to let him cope with the situation by sticking with it. When he has to be removed, you can let him know that he can return when he's calm and not crying. So, it's not the crying per se that's focused on, but the disruption that the crying promotes.