How to support from afar

My partner's dad was diagnosed with ALS last year and has progressed somewhat slowly since then- he can still walk a little with a walker, can talk, and can eat softer foods. My partner moved back home to help take care of his dad and is planning on being there as long as his dad is around. His whole family has a very pessimistic approach to his dad's progression, but I am choosing to be hopeful and can see him being around for years to come. It has been so hard for me to watch his whole family suffer from this horrible disease. My partner had to start a new job to be closer to home and is overwhelmed with the workload. When he gets home, he is helping around the house and trying to spend time with his dad, and I know he feels as though he doesn't spend enough time with me.

Has anyone had experience supporting a SO through this disease? I am unable to move to be with him, and it has put a massive toll on our relationship. I try to do little things, like send him coffee and visit most weekends, but I can't help but worry about the future- if he is this miserable now, how will he be when his dad has progressed even further? And how can I support him through this for potentially multiple years? Any stories of hope for couples and families like us?