You have to add travel time and check in to those times. At least 1.5 hours in the daytime by car to Heathrow from his place (I am assuming he would not go on the Heathrow Tube with all his stuff), plus 2h check in for international flights. So for an afternoon flight he would have to leave in the morning. Probably didn't hike his stuff to meet Josie so also add time travelling back from wherever they met. I don't think it works tbh.