Secondly, the comment was incorrect. Mary doesn’t always ask for a chapel to be built, or processions, or any of that. She often asks, but not always.
For example, let’s look at the only US approved apparition, Our Lady of Good Help in Champion, Wisconsin. At the same place on a trail, Adele Brise twice saw a woman surrounded by light. Initially reporting this to her parents, she thought it was a “Poor Soul,” somebody from Purgatory asking for prayers (ie, a ghost!) So she asked the local priest for advice, who said that if she saw such a thing again, she should ask the person, “In the Name of God, who are you and what do you wish of me?” (This is a very typical piece of advice that even comes into European folktales, btw, because of course a demon or evil ghost would not be able to lie very easily if explicitly questioned in the Name of God.)
So she did, and got the reply, “I am the Queen of Heaven, who prays for the conversion of sinners, and I wish you to do the same. You received Holy Communion this morning, and that is well. But you must do more. Make a general confession, and offer Communion for the conversion of sinners. If they do not convert and do penance, my Son will be obliged to punish them.”
She had some other people with her, who did not see the apparition, but who knelt when Adele advised them to do so.
Mary commented, “‘Blessed are they that believe without seeing.”
Then she continued talking to Adele, saying, “What are you doing here in idleness while your companions are working in the vineyard of my Son?”
“What more can I do, dear Lady?” said Adele, weeping.
“Gather the children in this wild country and teach them what they should know for salvation.”
“But how shall I teach them, who know so little myself?”
“Teach them their catechism, how to sign themselves with the sign of the Cross, and how to approach the Sacraments; that is what I wish you to do. Go and fear nothing. I will help you.”
And that was it. Mary did not order the building of any church or chapel; she just ordered Adele to get cracking on teaching kids their religion.
Now, there was a tiny oratory built on the spot within the next year, because Adele’s dad thought it would be fitting. Eventually a bigger chapel was built and approved by the bishop for saying Mass, and that chapel was where many people and animals fled, and were miraculously spared by the huge forest fire that engulfed that part of Wisconsin. Miraculous healings were reported to have occurred there, and still do. But Mary never ordered the building of a chapel; and obviously God knew that the people there would take care of it without any bolstering by orders or messages.
Another good example is the approved apparition at Knock, Ireland. Mary didn’t ask for anything. There was no message. The entire apparition was that a good chunk of the village saw the following things appear on the outside wall of the church building for around two hours: “The Blessed Virgin Mary, St. Joseph, St. John the Evangelist, and an altar with a lamb and a cross on it. Flying around the altar were several angels.” Nobody heard any of these people speak.
Villagers who did not see the actual apparition did see a bright light shining down upon the church, or in the area of the church (if too far away to see the church, or at a bad angle). Again, miraculous healings were reported to have occurred, and they still do. But everything that has been built at Knock has been built by the ideas of the people who live around there or who are interested in the place, not by any sort of order from Mary.
I could talk about a lot of other examples, but basically you just have to read approved apparition accounts and see which ones ask for stuff to be built and which ones don’t. There’s a fair amount of examples of each.
One important thing to find out is whether your friend believes that miracles do still occur (as believed by many Pentecostal, Methodist, Anglican, etc. churches), or whether he thinks that we’re all miracle-less since the death of the Apostles (a pretty common belief among some Protestant churches, since it allows them to totally dismiss all saint miracles).
Obviously, we Catholics do believe that miracles and prophecies and healings happen and that private revelations can occur, even though we also believe that God finished making His big universal revelations though the Scripture we have, and that we won’t get more universal revelations until the Second Coming, Resurrection of the Dead, General Judgment, new heavens and new earth, etc. (when we’ll find out all kinds of things).