Usage patterns
〈人〉が篤志家として活動するfor someone to be active as a philanthropist/volunteer
He has been active as a philanthropist for many years.
篤志家に登録するto register as a volunteer donor (e.g. for blood or organ donation)
She registered as a volunteer blood donor.
篤志家が〈物〉を寄付するfor a philanthropist to donate something
A certain philanthropist donated books to the library.