Yeah ..too much product [ depending on what one/s were used] can defeat the purpose and leave a system looking `dead`....the hair may be heavily-processed too and has no cuticle-layer, that too will add to the lifeless look. Sounds like there are a few things `going on` with it.
I only use Enhance leave-in conditioner and occasionally a little Brylcreem..that`s what works for me.... I used to use loads of things before ...all that happened was, build-up, leading to a lifeless,dull look, needing frequent shampooing.