The young pup will urinate when greeting adult members of her pack. This urination shows the adult that 1. the pup is very young (no hormones in the urine)
2. The pup is a member of the pack, this is her smell, so please don't kill me.
Best case. Dad does NOT acknowledge her at all. If she comes toward him when he comes home, he walks by her, no eye contact. She will offer this behavior for at least an hour upon his arrival, so if he can't ignore her, he should do something like feed her, when he gets home. focusing on doing something else is the key. If you want to continue to meet outside, that is fine, but don't work at getting her to calm down.. that just focuses her more on the behavior. Have him come into the back yard or wherever, pick up a ball or toy, and start throwing it around for her. If the two of you are there, even better. You both play catch with the toy for a couple of minutes, until her focus is on the toy.
If you do absolutely nothing about this, she will usually outgrow it. If you punish her for it, or focus on it, it will elongate the behavior. So, focus her on something else to do when Dad gets home, avoid eye contact, and go from there!