How do I tackle common aging issues like mobility problems with my dad? His knees are giving out and now its hard for him to get up from his chair.

Sounds like he might benefit from a walker. I know sometimes people dont want to "look old or disabled" but it's better than falling. When hes trying to get up it helps to move to the front of the seat and put his feet flat on the floor. Then push off with his hands from the seat or with a walker. Certainly a lift recliner would be helpful too.