No hobbies, interests, activities. Any advice?

Don't worry about it. Many times we think that an elder wants to still be active, but it is just how we think they might feel. We know that we would be bored if we weren't doing anything. Unless discontent is voiced, don't worry about it. Just enjoy spending time talking. Freqflyer had excellent advice of some easy things he might enjoy. It depends on what your father enjoyed in the past and how good his eyes and ears are.

Elderdog, is this in regard to your Dad who is living in a nursing home due to Alzheimer's/Dementia, as per your profile?

Is your Dad still able to focus on things? One thing elders love to do is talk about the past. Grab some photo albums of the family and have Dad go over the photos with you, and write on the back of the photos who is in the picture. I have a ton of photos but sine I have no clue who are these people, are they relatives or good friends. I am doing a family tree and names matched with photos would have been so helpful :)

What's the question? Does this refer to you or someone else?