Divorce and grandchildren? How do you handle occasions?

My father had not been at any occasion for me if my mother was there. The only exception was high school graduation, when they both left immediately after my receiving my diploma, leaving me alone (actually got a ride to a friend's for sparkling cider toasts.) It was a sad capstone to my childhood. He also missed college graduations (2 masters and undergrad), my marriage and the birth of his only grandson. Growing up, he never lived more than two miles from me. Now he lives in another state. He's never met my husband, but DS and I have seen him twice in 13 years. He has no other children, and just one grandson.

He's old and lonely, but if he had thought of me when I was a child instead of entirely of himself, maybe we'd have a closer relationship. I call him twice a year- on his birthday and sometime around mine, though he never remembers. My Italian MIL is horrified that I won't be taking him in when he is too infirm to help himself, not that he'd come.