Shower Pan Liner question

Hey Everyone, Quick question.My father-in-law is a contractor, and when I said I needed my shower pan liner replaced and the shower tiled, he said he could do it.From what I read online, it looks like he did it incorrectly, but he says its not a big deal. We already don't see eye to eye on anything, so I didn't want to push back, but just curious what you guys would think.From what I have read, there is supposed to be sloped concrete under the liner, he laid the liner right on top of the wood. Is that okay? via /r/DIY http://ift.tt/2tlK54U