My rude neighbor just put the centralized AC near my sisters window?

My neighbor beside us put the centralized AC near my sisters bedrooms window. Its so annoying that is so near the window too the heat coming from its back is flowing to my sisters window and she's complaining a lot saying her room is very hot. by the way we dont have AC we just have fan but despite using fan the heat coming from their AC is overpowering the fan air. My friend suggested me I should firewall our yard or build a wall as high as their AC in our yard so that their AC won't release the back heat to our window it just circulate in their yard since their yard is very near to us. Its so annoying and its very hot every time they use it. What should I do with it?
My rude neighbor just put the centralized AC near my sisters window?
My rude neighbor just put the centralized AC near my sisters window?
My rude neighbor just put the centralized AC near my sisters window?
Post Opinion