I haven’t read a comic book in years so bear with me on this question. All I know is that Bruce Wayne’s father (along with his mother) was murdered in robbery and that he was rich (how else could Batman later afford “all those wonderful toys”). I was under the impression Batman’s father was a doctor but I’m probably wrong.
He was a doctor.
The Waynes are old money who have been in Gotham for generations. I don’t know how they originally made their money but they were millionaires and I think they’ve updated Bruce Wayne into a billionaire. Waynes father was a practicing doctor though he certainly didn’t do it for the money. When Bruce came of age he inherited millions/billions in cash, stocks, and real estate.
If you read the first story as well as the origin in Batman #1, as well as the 50’s story “The First Batman,” you’ll see that Thomas Wayne was a doctor.
He was a doctor, and in Detective Comics #135 (Sept. 1956), Thomas Wayne wore a proto “bat-man” costume to a party, but was kidnapped by some thugs who needed a doctor to tend to their wounded boss, Lew Moxon. Thomas managed to get the jump on them and had them all arrested. Some years leater, Moxon got his revenge by hiring Joe Chill to shoot Thomas and his wife, Martha. supposedly, Bruce had a subconscious memory of his father’s costume and modeled his own after it.
Of course, the whole premise is subject to DC’s innumerable continuity changes, as described here in the summary for Batman #595.