“I asked him how he knew what was good. He said he didn’t, but his mom told him what wasn’t when he was a kid. “
That is a dangerous approach. You need to be able to identify both mushrooms to avoid (known to be dangerous) and then those you know absolutely positively are edible. You only eat those you positively know that are safe. Unknown, and known to be dangerous, you do not mess with.
I totally agree with you. You only eat the ones you are absolutely sure of. The slightest shadow of doubt means ‘leave it alone.’