My mother isn't interested. At all.
If she phones (and she usually phones when she thinks I'm not in so she can leave a message) she tells me what woes she is currently having, how tired she is, how she's not been well or is ill atm. She NEVER asks how the kids are or asks to speak to them. Even if I say they're unwell, she doesn't ask why or how they are.
Yet to anyone else who cares to listen, she'll tell them how she never gets to see them, how she grieves for them, she adores and loves them to bits, she has their photo in a frame (one that I gave her) and she'll put a candle in front of it. I am refusing to let her see them apparently, not that she ever asks if she can.
My father on the other hand, who now lives with his second wife in Scotland, always asks after them and dh. He asks how I am, what we've been doing, how my new job is, how dh's job is, how they are doing at school etc etc. To say that he isn't really a "kid" person, he cares a damnsight more than she does or ever did.