Hmm it seems like a very un-opportune time to wake up, if you want the information. Maybe your Mom wouldn't be ready for you to bring it up. For some people bringing up the past is too much. So if its your Grandmother's spirit maybe she knows this and is protecting your Mom.

(Just a guess, I don't know how open your Mom is. But for example, I have a question I really want to ask my mom about what happened to me as a kid. (More of the details) But I never get around to it because it was very horrific and she probably doesn't want to have to remember it.)

Other than that maybe just increasing your meditation might help with stability.

I think a lot of people (myself included) have trouble with dreams abruptly ending so just hang in there because I think eventually it gets better.