What does a lobbyist do?

My boyfriend is trying to join a firm to become a lobbyist. I dont know what a lobbyist does, how much they make, how many hours they work. Does anyone want to help me out? Like, will it consume his life? Will he have to travel? I dont really want to ask him, just because I dont want to offend him by saying something stupid, he rarely gets mad, but I dont want to demean him. Thanks