If any of you would like to see something similar...you can see it here in Iowa. A Priest built the "Grotto of the Redemption" in West Bend, Iowa starting in the early 1900's. He too, had been stricken with illness and vowed to build a shrine as he prayed for the restoration of his health. The Grotto is made of stones from around the world, and features the Stations of the Cross & a beautiful Nativity Scene amongst other things. It is stunning...truly something to behold if you are ever in the area.
Several buildings in my area, including churches, were made with that rocks-in-cement technique around the 1920s. It’s pretty neat.