Is it possible for me to steal a dog's loyalty?

OK folks here’s the problem: My grandma’s that lived with my other family have decided to move to another place where it’s impossible for them to keep a dog so she gave me this Pomeranian dog (I took him since it has been a long time since I own a dog and my grandma will give it to other people if I didn’t want to adopt him) that have been living with them for years (probably 6 years),they bought that dog while he was still puppy from a pet shop.

So now the dog is in my house,it has been about 3 weeks and I’ve tried to befriend him as much as I could but he seems so disoriented and he often ignores me. I have my experience when I live in my grandma house with this dog,he’s a good dog and will accept any kind of communication with me but I feel that he gives me ‘secondary or third class service’ and he gives my grandma and other member of this resident the ‘first class service’ when he responds to their presence. I know it makes me feel jealous about it.

He’s in my house now,well taken care,got his own territory (at least away from my cats),and have already got his medical check up. So how could I get his affection like the way he gave his ex-owner?