Do mediums call up the dead?

This is very much misunderstood, NO we don't, they're more alive than we are, it's the physical body that expires but the soul is eternal.
In case you didn't know it, they're are around you more than you realise and it's love that brings them closer.
They come back because they want to, and a medium can't force them, some don't come back at all if they don't want to. They come with love and concern for their family, for support and help with grief.
​They ultimately choose to come back