I had it written into my custody agreement that I can travel abroad for vacation purposes only. When I took my custody papers to get the passport there was no problem. My ds dad lives in another state and didn't sign the passport paperwork.
My ds is 8 and he won't address his teacher either (I'm a teacher so I understand). I have him write a note and his teacher was very receptive and told him he could even email her with his concerns. This has been very empowering for him.