As far as "I'm all about..." goes, it means that that is his primary interest, or at least it's one of them.
- My job pays well.
- Yes, but you work long hours.
- I do, but it pays well!
- I know, but you have to work with terrible people.
- Yes, yes. But I'm very well paid.
- Don't you care about the other stuff?
- No. I'm all about the money.
I'm making it clear that the money is my primary focus or concern. In the cartoon, he is saying that even though his help wasn't requested, he's very interested in volunteering generally. That's why he offered to help.