How do you deal with someone having a manic episode all over Facebook?

The daughter of a former friend is totally losing it on Facebook. She is finding meaning in everything and right now is flooding a Facebook post of mine with crazy comments about every 5 seconds. Everything is related to quantum physics and she isn’t making much sense. (Although to know nothing about quantum physics.)
I care about this young woman (in her late thirties) and I’m concerned that she’s going off the deep end. Apparently she recently left her husband and he has her young daughter (probably a good thing.)
I don’t rely have the energy to deal with her crazy but I also don’t want to abandon someone who is obviously headed towards a huge crash. I have a few bipolar folks in my family and I feel really selfish thinking that I don’t want the emotional drain.
If you have people like this in your life, how are you there for them without being sucked down with them?