I'm going to approach this from a different angle because it is the one I know. My dh died 7 years ago. The dc were really young. My family were supportive for about 6 months and after that, they started berating me for not getting over it. Fortunately, due to always having a slightly bonkers family, we had amazing friends and they carried me through the first 5 years. You don't get over it in a year, nor two years. I'm a really optimistic and positive, energetic person, but 7 years later I'm still thinking of my dh every day and we talk about him most days. We move forward with our lost partners in the centre of what we do, not on.
After 2 years, this lady obviously needs some support, but I do wonder if her family have behaved like mine, and maybe she had less supportive friends. I never took to bed - my dc were too young, but I can see why you might.
Has she found WAY Widowed and Young? If she was under 51, this is key to finding people who really understand.
I think you will have to approach it from a 'We want to help. What do you need?' point of view. You could suggest having the kids for the holidays to give her some space to get well, but be very aware that they may well be the only reason she is still alive. She needs some one to check in every day and some one who can listen. I know that can't be her ex, but maybe he still has access to her old friends.
Obviously, I know the children need to come first and I was always well enough to be able to put mine first. I know a lot of widows who go through spells when they are not. Joining WAY could really help (and we have a helpline for counselling too, as well as constant peer to peer support). I'm glad you both want to help, but your comment about moving on worried me. I'm sorry if my response is rather full on.