My son has recently separated from his wife. Some friends of mine have a single daughter who is a similar age to my son, and they want to arrange a set-up. Both of our kids have children and some other things in common from their past relationships and upbringings, but they live in different cities and my son isn't even divorced yet, so I'm not sure I want to get involved. What should I do?
You may have gathered so far in this column that I'm a huge proponent of matchmaking and generally bringing people together who might be able to make positive connections with each other. But this is a special case, and you're right to proceed with caution.
First off, your son isn't divorced yet. Whether or not his marriage is beyond repair, setting up a single mother with a not-yet-divorced man is a delicate situation under the best of circumstances, and even more so when the man is your son and the woman is your friends' daughter. Second of all, your friends sound like they're really eager to make this work. I wonder if their daughter has expressed interest in being fixed up, or if they're getting involved without being asked. Regardless, because both of your kids have kids and they live in different cities, a lot of pieces would have to fall into place for them to meet, and it would be hard to arrange a low pressure first date, which is generally the way first dates work best. If your son was single and your friends had a single daughter the same age, I'd so go for it, but there are too many other factors in this case, and it would be a shame for a failed set up to affect your friendship.
I'd recommend telling your friends that your son simply isn't ready to date yet. If they press the issue or bring it up again in the future, you can say that he's not in a position to be in a long distance relationship. Hopefully they'll drop it and you can go back to being friends instead of imaginary machatunim (Yiddish for the parents of a couple).
If you don't want to tell that white lie, you could casually bring it up with your son. If you choose to go this route and you actually think he might get along with this girl, tell him about the possibility as neutrally as possible so that he can make his own decision. While I usually suggest phone or in-person conversations for important topics, this is probably best done over email, so if he feels that you've overstepped, he can just ignore it. If you don't want to pursue the set up because of your concern for your own friendship, then give him a line like, "My friends really want this to happen so I'm just humoring them." Then you can tell them you asked and still use the above responses.
Right now, your son needs your support to pull his life together and to continue to be a positive parent to your grandchildren, and only you know the best way you can fill that role.