I'm friendly with a lady through a hobby that I do. We see each other every week and have been out together quite a few times, although we've drifted apart since I had my son last December. I'm pretty sure this distance is as a result of the fact that her own son died a couple of years ago at a very young age and that it is hard for her to be around babies or even to discuss them. I'm totally fine with that and I let her dictate the friendship IYKWIM. Anyway that's just background.
She's still friendly with her ex husband (son's father) and I've met him a few times. We're friends on facebook. His birthday is today and his deceased son had the same birthday. So far the messages on fb have made no mention of the son at all, which I find quite sad. I want to send him and possibly my friend a message acknowledging their son's birthday - would this be appropriate? Also, if it would, do you have any ideas how I could word it? The son died before I met this friend so I never knew him.