Well, I'm finding out more about the novel as I write it. I'm now doing a pov from Grandma's perspective. Her Granddaughter goes to visit Grandma often, and lets her talk about the old days.
I'm writing Grandma's memories in a kind of monologue at the moment, and I'm hoping that works. I say monologue because after an initial short para when Granddaughter goes round to Grandma's, the rest of it is Grandma talking about her memories.
The way I'm writing this novel now, with Grandma's monologues, I'm able to release information about things that might have played a part in making the MC behave the way she is. Of course, we can only rely on Grandma's memory of what took place, so that, in a sense, makes it unreliable, though still, hopefully, believable.