I agree that ignorance is truly bliss as a dub IF you skate on the surface mentally, have a strong social circle and manage to escape personal attacks on your family or yourself. Your friend is right that learning TTATT "disrupts the peace" Unless a person is fed up and disgusted with the religion they are better off living in their fairy tale world.
As a person who saw my father, four really close cousins, and my 21 year old son die while still a true believer, I can assure your friend that the hope of seeing them again was of ABSOLUTELY NO COMFORT to me. Grief is grief period.
I also witnessed both of my staunch MILS on their deathbeds dejected that they did not live to see paradise. They were so sure they would never die "in this system" (tm) that they made no preparations for the inevitable. I'm guessing your friend has not lived long enough to actually have his faith tested.