You have some great thoughts above and I am going to add my two cents. For various reasons including my disappointment in myself that I didn't write my Mother many times before she passed...I used the telephone mostly and flew to stay with her months at a time. She passed due to emphysema.
I believe sending notes and letters is a wonderful way to let your grandson know you are interested in what he is doing, how he is doing and how you wish you could be there. I think there are many lessons gained with sending notes and letter writing....including the memory of how we felt when we received them and looked forward to them. It might start something good. I am sure you will be told how he played via verbal conversations and technology, therefore you will know what exactly to say.
You have had to work your way through some hard times and decisions and as we know they often pop up when we least expect them.
It sounds like your family wants you to do what is best for yourself.
You will find your way and hope we have all given you food for thought.
Barbara