Can my manager give a less qualified/ inexperienced colleague a promotion because he "likes" him.?

Question

Ok,I have a one day a week job as a cook in a care home.i recently decided to look for a full time chef position.on line I noticed a full time chef position in my own kitchen.
When I went to work I mentioned to a colleague that a position was available. He explained that one chef was going on maternity leave for a year and that position advertised was actually going to the kitchen assistant,who has been doing some bank work as chef and the kitchen manager was going to give him the job.
However the kitchen assistant pointed out that the job was online and as far as he understood anybody could apply for the job,internal or external.

The kitchen manager is currently on vacation so I asked the home manager (highest authority) if it was possible to increase my hours anywhere in the firm.i had no intention of apply for the chef job as I understood it to be earmarked for the kitchen assistant (friend of the kitchen manager).
When I went to see the home manager I explained that the  kitchen assistant was been groomed for the chef job so I wouldn't mind taking his kitchen assistant role when he vacated it.
She promptly offered me the chef job which starts when current pregnant chef leaves.i asked do you mean the kitchen assistant job...she said no! The chef position. 
I accepted.
When my boss comes back, I think he will be cross,I wonder if the home manager is using this to show him who is the boss.
What do you think?
Also the KA really isn't up to the task but he is a lovely guy

Answer 1

Yes there is favortism everywhere. My bf was denied a promotion at work over a co-worker because the other guy was the manager's close friend. 

Answer 2

To answer your question, yes he can. But HIS boss can over-rule him.

Answer 3

If the "Home Managger" also has authority over the kitchen, which they may not, what they say goes. In my opinion I don't think they offered it to you just to throw their gavel and weight around. It seems like you might be the better choice for the position due to skill and knowledge reasons. The kitchen manager might attempt overthrowing it to help their friend out however they likely have less authority than the home manager so there isn't much they can do other than accept the home managers decision.

Answer 4

Sure, it happens every day.

Answer 5

You are aware that in 12 months time you won't have a job?

When she returns from maternity leave you won't have a position.  Your present job will have been filled.

UK.