¿Are we the best friend of each other?

It's been told that the dogs are the best friends of man (of the woman also obviously), but, have you ever thought if ¿are we their best friends too?.

Recently I have experienced some problems because of my dog's behavior, well to be honest it's not my dog, it's my girlfriend's dog which basically means that the dog is mine too. I have not been able to sleep well, in the early morning the dog starts to bark and acts so anxious, it seems that he listens to the neighbor and his dog going out to take a walk, maybe he also wants to go out or just thinks that there's a problem, but I don't think that because he always acts that way when is taken out to take a walk.

The problem might be deeper, more complicated, it's well known that dogs are very social animal, they need to be accompanied by humans or other animals, and this poor dog is alone along(during) almost all day while we are working far away, he stays at apartment with nobody to play, that's very cruel for a social animal. So he gets stressed, who wouldn't?.

When we get out, he stays barking at home, maybe feels that is going to get alone or maybe he only wants to go out with us.

When she returns home, the dog gets anxious and she can't control him, he barks so loud and jumps to her legs like claiming to be taken out for a walk. So at the end of the day she takes him out to take a walk and he comes back so happy, he obviously loves it, he meets other dogs, smells new smells, runs, breathes fresh air, is happy throughout the whole walk.

After returning home, the dog is relaxed, happy, but some hours pass and everything begins again.

It's evident for me that he is not happy, he stays alone for many hours, when he should be accompanied, when I realised all this, I wondered "He is my best friend, but ¿Am I his best friend?".