Perth:
I am very sorry to hear your mother is ill. I understand your concerns and although I won't claim I've been through the same thing, we've been through a number of medical situations in my family and what I found was that these times are not all bad. These situations forced us to have talks and spend time together in ways that might never have happened otherwise. I am not sure there is anything that makes loss any less than what it is, and it scares me too, so I don't want to suggest for a minute that there's an easy answer. But for my part, I don't think I would have had the opportunities I had to really be close to these people (parents, siblings, friends etc), if we hadn't gone through what we went through. Maybe you are already very lucky because it sounds like you're close to your mum and was to your dad too. So perhaps my situation isn't relevant to yours, but since you asked for ideas, that is what came to mind for me.
Ava