That father was not trained to go into a burning building (not from any of the information we have on him). He wouldn't know what would cause more problems in the rescue of his son by running into burning house. Firefighters do. He would in fact not even know where his son was, since he probably would have went straight to the bed, although it seems the son may have made it to the floor. Not being able to see the child on the floor, it is very likely that the father could have stepped on him, causing further injuries, possibly even ones that ended up taking his life before the fire or smoke got a chance. And then he could have become a casualty himself, and the firefighters would have to concentrate on trying to save both of them rather than just the boy.