Go to a good search engine and look up Dalton minimum or Maunder Minimum, show those to the friend. Plenty good reading out there. I have at least a dozen good articles bookmarked.
Also keep an eye on the Newsmax channel, they show the documentary Dark Winter from time to time. Newsmax also has it posted so you can see it about any time, very good show.
http://www.newsmaxtv.com/vod/Dark-Winter-DVDmp4/vid/Y3a3B3dDq20KqnLIU2Q8zVBUxzONK0G6/
Just a couple of the articles I’ve looked up...
http://www.thenewamerican.com/tech/environment/item/20630-scientists-debunk-climate-models
Several good articles here.
https://nextgrandminimum.wordpress.com/category/history/dalton/page/3/
This stuff is not hard to find, I use
www.duckduckgo.com
Thanks, very helpful.