Raising a second chihuahua.?

My mom has purchased another long-haired chihuahua and it's a few weeks old and will be arriving soon. I'm worried about how my almost 3 year old long-haired chihuahua is going to react to it, he hasn't got along with other male dogs but I've read that they get along with other chihuahuas. They're both male and the 3 year old has been neutered. Is there anything I should be wary of or certain things I should do?