Hi, I'm new here but wanted to respond to your post. I'm not sure of the other services, I can only speak from my knowledge having been in the Navy for 16 years so far. So, having said that; If Dad has physical custody of any type or time frame and is in the Navy or Naval Reserves, he should have a "dependant care plan" filled out and on file with his personnel office. This outlines who will be custodian over the children while he is deployed. It is a means of ensuring that they are cared for and helps ease some of that burden while he is gone. I don't know if this helps any. I may be way off as you may be asking a "legal" question. This may however, make it a little easier where the courts are concerned. Like I said...I hope this helped!
Shawn
Shawn