Fred, thank you for reaching out, we're glad to have you on the forums. I'm so sorry to hear about your loss, it's always tough to lose somebody special to us.
Grief affects us all in different ways, as Quirky has said. Some people like grieving alone, some grieve best in the company of others. Some people like to grieve through creative expression or keeping themselves busy. If you find that one way of supporting your father doesn't work, there are other things you can do to support him, and he may be able to guide you towards what this might look like.
Sacred has given some good advice here, in that little gestures of love will go a long way. Perhaps talking with your father about your own experiences and memories with your mother (or even photos, if you would feel alright to do this) may be a nice segue into a conversation where you can ask if there's anything you can do to support him. This may encourage him to share his own memories too, which could be therapeutic for him.
I hope this helps, please feel free to reach out if you'd like to talk some more or need more support. We're here and happy to help.
All the best, SB
