My parakeet just lost a friend so i got him a new one but he isn't to friendly, what should I do?

So I had these two parakeets named Zipper and Sailor. They were BEST FRIENDS and inseparable. Then one day they were hanging on a hook in their cage on our outside patio, my dad (who is very tall) walked without seeing it and knocked it off the hook. The cage fell apart and Zipper was molting so he couldn't fly but Sailor got away. We put the cage back together and got Zipper inside, luckily he wasn't injured. But Sailor flew off somewhere, and we knew from one time when we separated the two that they both started to flip out and were chirping for each other. So Sailor was gone and Zipper was all alone so my mom brought me to Petsmart and I got a new parakeet, we asked the gender and the lady said that it was too young to tell what gender but she guessed it would be a girl. I named her Lila and she's a very pretty bird. We put her in the cage and they don't fight but they don't interact and sometimes Zipper nips her to keep her away from him and one time pushed her off the perch. I REALLY hope that Sailor is okay and that he might return to us but those chances are slim to none and if he did he would be traumatized. What should I do to make them friends with each other? I know that I should just wait but I can't help but worry. I don't know if it matters but none of them are hand-trained. Please help me.