I work in a security company. Due to some closures my grandma and grandpa work at the same site as me for the same company. I was reciently given a supervisor position on the weekends but come to find out that my pain in the butt grandmother doesn't want me being above her. So she picks out the place in the handbook that states that family cannot supervise family. She has crossed me twice now and is really starting to get on my nerves. The boss is now deliberating with a higher up to make sure that I can become her supervisor. I have been supervisor before but stepped down because I moved away and came back. In my opinion they do not have the right to tell me I have it and then take it back away from me. What does anyone suggest I do? I want my position back and I am just about willing to get this woman fired in order to do it. I don't really care that she is my grandmother. I think I may have less seniority than her but my company has bent over backwards for me several times already on top of moving three people to get me the shift I want... I wonder if I can fight this.

Not really fight it, but you can explain this to your supervisor.

They have the choice to move her to another shift of course

I hope they do. I loved being supervisor and I was very good at it. This is why they pushed so hard to get me there in the first place