Continuity mistake: When Mr. Roper tries to explain to the girls and his wife what he was doing in Jack's bedroom, watch over Mr. Roper's left shoulder on the shelf. The number of yellow cans on the shelf keep alternating between one and two cans throughout several minutes. In addition, also notice the suitcase on the floor under the shelf as well. Whenever one yellow can is shown, the suitcase is by itself and whenever two yellow cans are shown, there is a square silver bag in front of the suitcase.
Continuity mistake: When Mr. Roper does the card trick. Mrs. Roper says it's the 2 of clubs. We see it is. A second later we can see for a second it's a face card.
Continuity mistake: During the kitchen scene when Janet is eating the egg salad sandwich, her yellow napkin is tucked in her blouse and then disappears. She then tucks another yellow napkin into her blouse.
Answer: He's not a Catholic priest. He's a pastor, with the title Reverend, at a community church who chooses to wear a clerical collar. Some people still address pastors as "Father" though. I'm not sure of his religious denomination, but most pastors can marry.
Bishop73