Gerbils are great but if you get a boy and a girl, you’ll have lots of gerbils very quickly. I know this from experience even though the pet shop owner assured us that they were both boys.
Once we got that all sorted out, we became very good at sexing them and soon had two cages for them. Girl gerbils are very good at escaping and unless you have a glass tank, they’ll almost certainly get out somehow.
And no. He’s seven. It doesn’t matter what he says, you’ll be the one cleaning them out, feeding and watering them.
But they are fun pets and are much better than hamsters. They’re not nocturnal, they’re active during the day and providing you interact with them regularly, they’ll trust you, eat out of your hands and let you touch them.