I often fly for Angel Flight South Central. They don't require a copilot, but they do encourage the use of "mission assistants".
Mission assistants are usually pilots who are new to Angel Flight, or who don't yet met the requirements to be a mission pilot. They are themselves members.
It's very very helpful to have an assistant on an Angel Flight, it takes a lot of stress out of it. Here in the South Central region the AF office will find an assistant for you if you request one.
I can understand why the inital poster would like to have some help if he is flying Angel Flights, and I'd suggest he just ask the office to help him find an assistant/copilot.