I'm with you, iscandara. When my uncle was dying of brain cancer nobody told me to stay away or prevented me from going to see him, but my family just didn't visit him nearly as much as we should have. I could have gone by myself, but I didn't. It pains me to think about it, not only because I wish I could have spent more time with him when he was alive (even if he wasn't "all there" toward the end), but also, frankly, because I feel so guilty now for not being a good niece to him when he'd been a good uncle to me.

The LW may or may not regret having missed these opportunities to spend time with her grandmother if she opts out, but I can't imagine her wishing she hadn't visited after her grandmother is gone.