Like most popular social media sites, you usually won't see very valuable discussion in the comments, at least in my experience. It's mostly for people to post news, research, and so on, and follow the big names or organizations in their field.
Most of the valuable information is diffused via posts but I do put a bit of time and effort into trying to filter out all the crap posts like memes, the faux inspirational stuff, self-aggrandizing nonsense, etc.
What matters is the signals she gave him and how he read and responded to them.
If she gave signals of "please leave me alone" then whether he's creepy or not depends on how he responded, regardless of how he looks.
Him being a positive and personable presence near her over a stretch of time, especially if she gave signals of being in the neutral-to-positive range towards him, is fine. The most important thing is that if he eventually shot his shot - and the response was "no thank you" - that he accept this answer gracefully.
Lots of women actually prefer to meet guys through their social circle because it's an easier way to meet guys who their friends can give their own impressions about and who are less likely to be assholes. It sounds like it turned out well here, although we're missing a lot of information.