Oh for goodness sake, the scaremongering and misinformation on this thread is ridiculous, mostly from people who by their own admission have not and will not ever forage.
Firstly, your son is correct. Some species are really easy to identify like giant puffball, dryads saddle, chicken of the woods, some of the parsols etc.
Three things you need to do:
- join the FB groups and just observe the posts. This helps to become familiar with the common types
- buy the book Mushrooms by Roger Phillips. He photographs and puts them on the page next to each other and it will make him a lot less comfortable when it comes to IDing which is exactly what you want. 99% isn't sure enough to eat
- have a browse around the First Nature website. It shows you what common types can be confused with ones that will make you ill.
People that tell you they have an app that can identify mushrooms are talking out of their arse. One of the main ways to identify a mushroom is by smell and if your phone is doing that I'll go out and buy the same one tomorrow. The second way is with a spore print, ditto my above comment.
ABSOLUTELY pick them to bring home and identify, it's the best way. Do the aforementioned spore prints too as well as cutting it open and examining it all.
But my final point is one that everyone misses about mushrooms - they aren't just edible or poisonous. They do SO many other things. Some are medicinal like the birch polypore (which are also fun to make little plasters with as they are antibacterial), King Alfred's cakes you can light the inside of and play with that (it's like charcoal), dead man's fingers are just really cool to look at and artists brackets you can draw a picture of. Oh and there are some really cool ones that stain blue when you cut them so you can write your name in them if you're quick.
PM me for more info but you should definitely do this with your son, its lots of fun!