The classes I seen do have places to show terrain and even for new people to find mushrooms. But individuals, well we don't have places for such things. I just have places were I know I can find mushrooms on a good day. And that's it.
It would be impossible for your friend to create all the proper conditions for many mushrooms to grow in his backyard.
Don't think I've ever heard anyone say three point five" HDDS or read it in the decimal form-- Three and 5 tenths. It's always said as the fractional form-- 3 1/2".
I think they mark them as 3.5" because it's easier to typeset a decimal than fractions. Even those accursed 3 1/2" floppys seem to be marked 3.5" these days.