It's never to late Caroline & Charlie is still only a baby.Pick a time in the day when you know charlie may be more active & of course Dave is home.Let them have some quality time alone,say only 10 minutes to begin with, you & the kids need to leave the room.Let Dave give Charlie his full attention, feed him his favorite treat,chat to him,play a game & of course if Dave can get charlie to step up that would be a bonus, but that will come in time.Dave must do this consistently every night & if he has time at the weekends perhaps twice a day.The more they interact together the more confidence Charlie will build up in Dave