Once, when fed up with this during a discussion on a small moonlighting job I said "Yeah, kids are pretty good with this stuff these days, Tell you what - have him get started and I'll be available to give him any help he needs at 2x my rate".
I responded that he was the one who had reached out to me, and if he feels like his son can do it then he shouldn't have wasted his time trying to find a contractor since that will be more expensive.
The client didn't like the attitude and I didn't get the job, but I was kind of glad because it was pretty clear to me that he would have tried to weasel out of paying me regardless.