I know that it would not be the same as giving to your own family, but have you thought about when they do the collections for Christmas in the supermarkets for a charity where children do not receive a present from anyone else?
If your GS does not want you to contact him and he has sent money given to him by you back in the past, then I cannot see him being ok with you sending anything again.
But to make your Christmas feel a little better, then maybe give to a child who has no one to send it a gift? That way, you would feel a warmth from still giving, the child would receive a loving gift and your GS would learn that you are not bending over backwards to be ok with him. I would send the family a card and leave it at that. And with your husband having been unwell, I would concentrate on him and yourself and go away and put your feet up for a well deserved rest.
If your GS can't sort this rift out before Christmas, then he doesn't deserve the head space it is taking up for you to worry about it.
I personally have an ED, this will be my third Christmas of not seeing my grandsons. I will make no attempt to do so. Instead I am doing a charity Christmas. I will take my doggie and go to the PDSA, who treated her broken leg a few years ago, and make a donation to them. I will also give a gift to a child/ren I don't know, through a charity. That way, I still get to buy children presents and have the feeling that someone somewhere is happy that I exist. Unlike my ED, who couldn't care less if I am here or not.
Sometimes we have to move on and just do the best we can with a bad situation. But I refuse to have it spoil my Christmas from now on, I worked hard for many years to make my children's Christmases perfect, they wanted for nothing. I deserve now to have my Christmas my way, free from sadness.
(My ED didn't even get in touch or send an e mail when I lost my dad this year.)