If you would like to connect with someone you love in the spirit world during a healing session, praying for that ahead of the appointment time, is very powerful. I ask The Archangel Michael to oversee all of the spirit communicating that I am involved in. Mediumship does occur in most of the healing sessions.
A medium does not have control over which spirits come in. They do have control in that the only beings they connect to are ones with messages of love, guidance, and or forgiveness.
The heart goes on forever, as the song says, and now during this time of conscious awareness in the new Aquarian age, more of our loved ones are working in concert with the angelic and galactic hierarchy, to help their families here on Earth.