Those who do that aren't truly spiritual but still controlled by ego.

And that is understandable when so many have been taught since childhood that worshipping Jesus, rather than God, will bring you the reward in the afterlife of reuniting with your family and loved ones. That isn't how it works. These 'lives' we're living, these personalities, are illusions that are cast off by our true Selves We will still be the same selves we were in this life, only more so than can be imagined while in this world. If you are 'Steve' in this life you will still be 'steve' but will know that the 'Steve' of this world was mere illusion.

But, if one's beliefs bring comfort I see no reason to disabuse anyone of their faith, especially an older person who dreams of seeing a child or parent again. That would be a cruel thing to do, even if you know that person is wrong. And cruelty is not a spiritual thing to practice since it comes from ego, not Self.