Hun that sucks that they are pushing him into something he doesn't want to do!

You'll need to check his employment agreement/contract: that will stipulate what he is and isn't expected to do. If the contract doesn't state anything about working registers, then he could stand his ground and say no, he isn't going to do that.

But I'd hazard a guess that there'll be a clause in there saying something about covering "other duties" when required. It seems fairly logical that a retail store would cover their bases like that in case there is a time when maybe there are two people working wines and the registers are flat out, so he can be called over to registers to assist. Or something similar.

Another thing he could do is get in touch with the union - I'm guessing you guys would be covered under the SDA - Shop, Distributive and Allied Employees Association. Is he a member? They would be able to advise him what his rights are.

Changing to another store might not help... start with his contract and go from there.

On another note: why does him changing stores impact you? Don't quite understand sorry...