brain injuries are tricky...I imagine most people may not ask, especially on a public forum such as facebook. and if all you are offering are updates like you posteed, you are not suggesting that there is a mental health issue or component so many may not even think to ask either. they may not even relate the two (if there were no mental health issues prior to the brain injury).

if you want folks to ask, mention your mental health, say you are struggling, not struggling or ask for help. then you will get feedback. people don't ask about your broken leg if they can't see it is an issue (and you walk just fine).