I think that the OP means that she helped him with the paperwork/tax side of thinks, not with money, so she knows he has £2k spare/disposable income each month.
OP, I agree that it's a stingy amount. I've got a lot less disposable income but spend (like for like) more, as does everyone I know, on their children and Grandchildren.
What's more important is the lack of interest. I don't know one Grandparent that comes for Christmas Day, but hasn't asked what the children want/what they're doing and joining in, if possible.
Yeah, he's a shit Dad and Grandad, the pub atmosphere is the most important aspect of his Christmas. You've long ago established that, there isn't going to be a Christmas miracle and him transforming into a loving DF/GF.
I had abusive/uncaring parents, you can't change that. They will never be the parents that you wanted or deserved.
You've either got to go NC, or limit contact and accept this is how it is.
Don't let this put a damper on things. Deal with the emotional side of having a emotional distant parent another time. Christmas brings this sort of stuff to the surface.
I would look on the relationship board, look at the links given on subjects and see if they ring true and reading them helps.
As for those quoting they've lost their DF/GF, you've got to have them, emotionally, to lose them.
It's my first Christmas without my Mum, she died this year. I miss her being around, sort of and shopping for her, but I haven't lost someone who would enjoy the day properly and who would ever offer emotional support, someone I could talk to etc so you don't 'lose' them in the same way as someone else.
The money is the symbolism of the OPs missing out on a caring father, not the amount, she's just posted too soon after the event to explain that.