Is AUTHOR wrong in the post ? POST : To start, I'm an 18 year old security supervisor. The site that I manage isnt difficult and is very laid back. The only people that work security here are me and one other person, who I manage.

The other security guy i used to work with recently got fired. His replacement was an older guy (late 60s) that I'm going to call fred. Fred was extremely incompetent at first, he struggled to understand basic concepts and was very hard to train. I eventually expressed my concerns about fred to my OP manager and they said they would see what they could do.

 After about 3 weeks of having this guy work with me, I got a call from another security guy, I'll call him rob, who is pretty good at his job, he tells me that he is losing his job at where he works, and wants to come work with me. At this point, fred was still not doing to well, and I told rob that I'd be glad to have him instead of fred. 

Every week I would get a text from rob asking if I could call him. These calls would be short, but rob would always be asking me questions about things I cant control, like his start date, when to get his uniforms etc ( I dont control this stuff, our branch takes care of this stuff). Every call, I would get a sense of entitlement from rob, he acts like people owe him this job because he has Bill's to pay, and has nowhere else to go. He constantly talks down to me, talking about how I dont know his situation, and acts like he knows everything because hes been working security longer. Every call was like this.

Now that a couple weeks has past, I've been able to work out the kinks with fred, and hes finally doing a pretty good job, no recent screw ups. Today I got a call from rob  stating that he will report in this next Friday, and after a bit of conversation he revealed to me that he would leave if his old boss told him to come back. This would make a headache for me since I would spend a bunch of time training him, for him to leave so that I could just end up training someone else, that could end up being unreliable (hard to find reliable people around here). 

Fred on the other hand, is and older guy that collects social security, and is very unlikely to leave. Hes not the best, but hes reliable and he doesnt talk down to me. I have to say, I dont really want to kick fred for rob, even if rob might be a little bit better at the job.

WIBTA if I denied Rob the job I initially said he could have?

TLDR; Fred isnt the best but hes reliable and he doesnt talk down to me. I told Rob that he could have this job, but I later learned that he acts very entitled and talks down to me a lot because I'm younger. He may also prove to be unreliable, and may leave later down the road, causing a potentially big headache for me. Fred is very unlikely to leave. Rob is slightly better at the job than Fred is.

First time I've ever had to make a decision like this, so any help is appreciated.