I'm sorry to hear about your mum. I agree that grief, and the stress that accompanies it, can be very bad for your skin so I'd also cut yourself some slack.
I'm 46, have very dry skin and it's definitely getting a little more tricky now.
I have been using an oil based cleanser for years. I used just plain almond oil for a long time but recently swapped to Green Clean from Farmacy which I love. I am not sure it does a better job but the way it makes me feel is worth it even though it's ridiculously expensive.
Agree with other posters that a Hylaronic Acid based moisturiser is important. I use a neutrogenia night gel. Stick with your vitamin C but I'd swap it to the morning as it helps to protect your skin when out and about.
As you get older, more exfoliation is necessary. I'm using an acid exfoliator/toner in the morning and, when I can be bothered, a Clarins face peel. I should TOTALLY use the face peel weekly - it's astonishing what it does to my skin. Makes me glow, and makes it smooth so that make up goes on beautifully etc.
The primer I'm always advocating is the Bobbi Brown Vitamin Enriched one. I find it has a lovely moisturising affect as well as being a good primer. It does have quite a strong scent though so definitely don't buy it without trying first in case you don't like it.
My favourite foundations have been Bobbi Brown as well for a long time but I've struggled to get hold of the one I like so I'm using a NARS one now. It's nice, but I've found it really does need to be applied with a brush or a sponge as otherwise it's a bit cake-y.