Hi, sorry your Mum is faced with surgery so soon after her diabetes diagnosis, tell what are her bg readings like? Is she taking any medication, eg Metformin? If so Metformin needs to be stopped 48 hours before any surgical procedure, so make sure that surgeons are aware if she is on medication.
As per that above posts, its important that her bg is well controlled, and make sure that Mum is eating really good and healthy food, and maybe even take a good vitamin/mineral supplement as well so that she is well prepared for the surgery and as healthy as possible this will help her recovery. I know plenty of people who have had hip replacements and are once again able to walk really well and no more pain.
I hope all goes well for you all, and yes, do come in and ask away, there is always someone here to give really good advice/suggestions.
All the best
Karen