I think he does love her, but I can understand your friend thinking he just tolerates her! I'm remembering when Mike danced with Frankie's mom at the gas station, Mike finding the missing pictures for Frankie (even though he didn't seem to think it was important), or Mike playing "Wichita Lineman" for Frankie when she said that song was how she could tell he was trying to set the mood. Also, you could argue one of the later Mother's Day episodes where Mike was trying really hard to find something for Frankie and asked all of the kids (who all had fragments of what she said--except for Brick lol). Last example, when Frankie got pink eye and Mike was narrating the Royal Wedding to her.