Dear starchaser, rather than look at your transits and offering what might turn out to be false reassurance, I would like to take a look at your natal chart for the strengths you can draw on to help you deal with this situation.
What I notice right off the bat is that Moon in Gemini. The Moon suggests how we react at our most instinctive, basic level, and so could be said to have something to say about how we respond to stressful situations. Your Moon suggests that communication is vitally important to your emotional wellbeing, and I would recommend that you draw on this to help you deal with what's happening. Talk, talk, talk - talk to your mum, to her doctors, to her nurses and to your friends. Get as much information as you can - look on the internet, communicate with other people going through the same thing. This may mean you laying your emotions bare and with a 12th house Moon, that may be difficult for you, but remember the 12th house also describes our "hidden enemies", which implies that not acknowledging and talking about your feelings might be particularly unhelpful for you.
Your Moon trines both Mars and Jupiter, in a grand trine pattern. I think what this could signify is that you have enormous emotional strength. It also suggests that perhaps faith might be important to you, or some kind of philosophy to help you understand the role and meaning of this situation in your life.
My own mother died 5 years ago. It was, of course, a terrible dark time of my life, but I got the chance to spend a lot of time with her before she passed and I treasure that precious time. I also feel that this bereavement made me a stronger person and gave me some much needed perspective in my life.
Look after yourself.