I would have left it alone because by the time I saw it, I am pretty sure someone a lot closer to her would have seen it and taken care of it.
A friend a few years older than I am sent a note on Facebook to another friend about the loss of a loved one, basically, "I am sad for you. LOL!", thinking that meant "lots of love", which it did many years ago. Oops.
Older people do know often what some things mean. It is kind of offensive to me that people think they are putting something over on me. I either look it up or ask, as you may have noticed. If it comes up with someone really close, I will mention it, but I never laugh behind her back about the situation, as some do. (Not in this thread, however.)