Just a forum member and I am not sure if the coconut oil can still penetrate the hair with silicones present. The Brains would have to answer that one.

Why not just remove the silicone buildup? You can do it several ways. There is a powder product sold at Sally Beauty Supply that you mix into a gel which will remove buildup. Or you can take plain old baking soda and mix it together with your shampoo in the palm of your hand and shampoo as usual. Be warned doing this will dry your hair out quite a bit so using a conditioner is important. Maybe one with no silicone so you can be sure the coconut oil will work as well as it can?