dog coping with losing a friend dog

[melody]

My friend has a male golden retriever given as a gift to her. She also has a female beagle then, but the two got along very well. They were very close because when I visit my friend's house, these kids play along together and barking together. One day, the beagle got lost when the door was left opened and my friend really was not able to see her. PJ, the male retriever, was devastated, I think, as my friend tells me that he was not barking and playing already. He was always staying in a corner doing nothing. And one time, when my friend tried to call him for a bath, PJ is already snarling at her so she had to call her brother to leash him and give him the bath. Do you think it's because of his friend beagle? We call her Poochie. I'm already searching on how we and my friend can handle it as we sympathize with PJ.