my father hasn't put the baby down since he arrived on saturday

my parents are here for two weeks. according to my mother, my father never once held me as a baby. he was always at work, or he 'didn't know how'. now he walks the corridor with my son for an hour after lunch, humming old film songs, and won't hand him over. my mother watches from the sofa with a look i can't read. pleased or annoyed, i can't tell. maybe both.