I was living in England as a young Anglican priest when my younger brother came to live with me. Some weeks after his arrival he learned about the death in a plane crash of a young friend of his we shall call Tom. 

Tom was about 5’2″ with a shock of blond hair, a round tanned face with freckles. He was brought up as a Baptist, but had never been baptized and he was in a state of rebellion against the faith when he died unprepared.

My brother Daryl told a priest named Fr. Philip about Tom and the priest said, “We must have a requiem Mass for Tom.” So the two of them got together with another priest named Fr. Roger. Fr Roger agreed to celebrate Mass for Tom’s soul. They decided that it would be best if the Mass were a semi-private celebration, so they went into church and locked the door and proceeded to say Mass for Tom.
Fr. Philip was an extraordinary man with a gift of second sight and the ability to read souls. This spiritual or psychic gift was a benefit to him in an active healing ministry. As the Mass proceeded my brother was overcome with emotion, and at the point of kneeling to receive Holy Communion he felt that Tom was actually there with them and that he was disturbed and confused by what was going on. Daryl (my brother) said that he felt as if Tom was there next to him at communion and he re-assured Tom that everything would be alright and urged him (in his mind) to simply accept the gift he was being given.
After Mass Daryl recounted his feelings to the two priests. “It was like Tom was actually there!” 
“Oh he was there.” said Fr. Philip, “I saw him.”
“What do you mean you saw him?” 
“At the offertory a young man in his twenties came into the back of the church and came in to join us. I was surprised because I thought we had locked the door.”
“I did lock the door.” said Fr Roger.
“What did he look like?” asked Daryl
“He was about five foot tall with a round face with freckles, and lots of blond hair. He was wearing boat shoes, khakis and a polo shirt.”
“That’s Tom!” Daryl said. “You mean you saw him like a ghost or in your mind’s eye?”
“No,” said Fr Philip, “I saw him as if he was a real person. He was as solid as you or me.”
“What happened?” 
“He came in and knelt next to you, and then after communion he went up into the East end of the church and disappeared into the morning light.”
“So Tom was there! You saw him!” Daryl said.
“Yes” said Philip.
“I saw him too.” said Roger. “Not with my physical eyes like Philip, but I could see him in my mind’s eye, and Philip’s description matches the boy I visualized.”
The experience impressed both me and Daryl and took away any Protestant doubts we may have harbored about the efficacy of offering Masses for the repose of souls. 
It also meant that when the time came to enter into full communion with the Catholic Church the way was easier, and it also means that (now as a priest) the gift of offering these masses and the celebration of All Souls Day is especially close to my heart.