Let them worry about that. Hes asking for advice. If you don't want to give it. Then don't. Don't worry about their issues. Hes a grown man I'm sure. Hes built engines before. Surely he knows what risk hes taking. If he feels he can tackle it. Let him. Thats not for us to determine whether he is capable or not. He wants advice on some good parts. Its like *****y women around here. Anything to argue about. I know words can be taken the wrong way since your reading a keyboard. Let it go. Give him some advice or ignore it. If it frustrates you don't read it.
Just what exactly do you think he has gotten? If someone asked you which was better to cut their wrists with, a razor blade, or a steak knife would you not feel inclined to advise them against cutting their wrists in the first place? Even if they were a "grown man"? Sometimes the advice people need goes a little deeper than the initial question they ask.
Anyway, have at it. I've given mine, it's obviously falling on deaf ears.
Best of luck.