My best buddy has been FWB w/this girl for 5 months now?

As far as we know he is her only friend w/benfits and she is 3 months pregnant, (they said the condom slipped) But they say they are not serious, but here's the thing they go out to eat and to the movies every other weekend, at least twice a week she will come over to our place (I am roomates w/the guy)They will sit with all the lights out on the couch and watch tv w/his arm around her when no one else is there, but if I am there they just hold hands and watch TV. There have even been times that he will call her and say I am going to, let just say Steak and Shake and then he will ask her do u want anything. Now she has started to call him "baby" and he calls her "Baby Doll" They call each other every night and talk for a least an hour. Please keep in mind that he has been married twice and has 3 kids and her first and only divorce has been final for 8 months. What I am wondering is do think they are into each other more than what they are claiming?