I also agree with Vicky and was going to suggest meeting the guy and listening to your instincts, but it was too late as Holly had made her decision.
Good advice if it comes up in the future, though.
This may be a US/UK thing or a regional thing, but taking in lodgers up here in the North is much more common than I would ever have imagined. My MIL always has strangers living in her house whenever I am over there. My BIL and his family have been renting to lodgers; they've just bought a new house and are keeping the old one so they can continue to rent the rooms.
So not weird at all for a man in his 50s to be taking in lodgers of either gender.