Sounds like a tricky situation, maybe you could text your cousin and just say something like "I hear your having a tricky time at the moment, if you ever need to chat you know where I am" ... I wouldn't feel pressured to get involved if your not sure though, it sounds like they have the right support in place ...
If she does approach you, maybe you could direct her towards this site, there's lots of distraction techniques on here and basic first aid advice which could be useful to her ?