I can't believe my manager

I was recently put up for a promotion, if you will. I went from being a project coordinator to sales support. The head of sales resigned and I was tasked with some of the things he was doing, and instead of reporting to him I now report directly to the M.D.

My manager, who always claims she's looking out for the best interests of everyone and the business, phoned me to ask if I was happy with the change and what's going to happen with the tasks I'm doing now. No one else has the capacity to take on new work so she said we'll have to hire someone else. I mentioned my sister was looking for work, she has the same work ethic as me and she'll be will be easy to train because we can work together. My manager seemed to think it would be a good idea.

Later that day she messages me and tells me no, she thinks it would be better to train someone else to take on the sales support position I was offered (and already familiar with because I was already doing some of the things). I told her I was happy to take on the new role and the new work is more complex than my project coordination work. That was the last I heard of it.

She never asked for my sister's CV, so I assumed it was on hold until people were back from their Easter leave to discuss.

Then yesterday she messages me about a new lady, Jackie. She literally referred to her as the new person. She wants my opinion about something. I thought, OK, they decided to hire someone else, that's fine.

I was then speaking casually with my other coworker who tells me Jackie is the managers SISTER. She stole my idea to get her sister a job.

What makes it worse is she never even asked for my sister's CV, to see if she'd even be a good candidate AND she never gave my boss the opportunity to make an informed choice AND then still refers to her as the new lady as if she didn't want me to know it's her sister.

I'm so annoyed. So so SO annoyed. It's probably for the best because I don't want to subject my sister to this nonsense, but still.

@Michelle, the position wasn't advertised, and I told her to let me know when my sister's CV must be sent. Her sister lives in a different province so my boss wouldn't have even have had a face to face interview like I did.