What to Do About Friends

Long story short, I love playing the game and trying to climb with a buddy or two of mine. Most of the time it's pretty good fun and I feel like we are learning more about the game each time we play and improve our decision making, shotcalling, map awareness and such over time. However, and this is the big part, he is the type of person that gets really defensive when you try to tell him that you think he's doing something wrong. Case in point, this last game we played he played Jayce mid and I played Kennen top. I'm going pretty standard items and such with the protobelt, zhonya's, etc. He, however, starts with a tear. I have no problems with that, but then he proceeds to build essence reaver, dominik's, BT, and just overall items that have no synergy. Now he usually tends to know what he's doing on the champs he plays, but this is one of those times where I just couldn't understand what he was trying to accomplish with that itemization. Surely if you go essnce reaver you should stack crit on top? He actually does the same thing on blue ez just to get 40% cdr by buying essence reaver after tear, ibg, boots. Not only that, but he doesn't even upgrade the tear into manamune before getting all his other items which completely negates the mana to ad passive and practically plays the game having no damage whatsoever. Basically, I really wish I could speak my mind to him but already know that he's going to react in a very negative way because I'm basically telling him his way of playing the game is wrong. Just not sure what to do when situations like this happen. Anyway, that's my short story/rant. Anybody else have any similar experiences? Feel free to share down below and start a discussion. Maybe we could all possibly help each other out with this problem??? Anyway, have a wonderful day and happy forum posting everybody!