I disagree that he is trying to dominate the female.
I have a similar situation here. Every morning, my bitch would dash out the door ahead of my male, then as soon as he came out, turn and bite him playfully on the neck. I THOUGHT this was dominance behaviour, until one day, I bought some rawhide bones for the dogs.
I spread the bones around the room, leaving an extra one in case someone took another dog's bone.
Ranger immediately claimed ALL FOUR BONES, and the other two dogs were afraid to go near them!
Once he settled down to chew on one of them, I was able to give the two females their bones, and there was no problem.
So, the biting of the neck does not necessarily indicate he's truly the alpha in the pack. A senior dog may not have the physical strength or speed to dominate a stronger, younger dog, but they may still demand that dog's respect due to their age.
Please note what she says: "The only time he badgers the female is when we first go out and there is no ball, his body language to her is play. Unfortunately she is not physically able, after a few attemps she will put him in his place."