Did he make them all himself?
“I have just begun my 147th castle in Lego”
Looks like it. That’s 146 more Lego castles than I’ve built. He doesn’t give a date for that but at the very least, this site was updated in Feb 2015, so it looks like he’s still actively maintaining it. I did not know about this site, and there’s clearly a lot here to look at, so I expect to be going through it for some time.