Is it helpful to channel the conscious mind of comatose people to coach them about crossing over, or is the deep subconscious the level most needing help? What is most helpful to tell them?

The deep subconscious is the most important component here and is often the roadblock as well. In the same way that deep inner fears can constrain the happiness and functioning of a person without their real awareness of the reasons why, the deep subconscious can trap a person and prevent the transition because it is holding on for dear life, literally, and will not let go of the reins. This level of the mind can be given healing attention and using the HMR process to address the current concerns and dilemma as seen by the subconscious would be the first step. This again is not intended to do manipulation but render assistance, and sticking to the protocol of the HMR process to be non-leading but rather facilitate a healing for the inner confusion and fear. This would be the very best way to prepare a person for successful transition who is stuck with a nonfunctioning body and cannot let go.