I didn't address anything from a moral standpoint, just a legal one.
The law says he cannot adjust based on a US citizen parent, but he can based on a US citizen spouse. The law also says he cannot re-enter the US for 10 years after overstaying for so long. I didn't write the law, that's just what it says.
The law also says that if he makes a material misstatement on his DS-230 to get an immigration benefit, he is permanently barred from entry into the United States. That's FOR LIFE, FOR ANY REASON, and there is NO WAIVER. That's also what the law says.
If you believe that a young adult who has spent the majority of his life can successfully impersonate a native Peruvian in front of a consul who sees them every day, be my guest. He might. I don't know. I do know that consuls aren't idiots, their job is to detect fraud or inconsistencies, and my bet is that he is likely to be discovered, especially since they deal with native Peruvians every day and can notice differences in dress or accent.
If the consul detects the fraud, then junior is spending the rest of his life in Peru, or at least outside the US. If the consul discovers that Mom lied on the I-130 and reports it to ICE, she can be prosecuted for immigration fraud. She won't be deported, but she will be a convicted felon with significant negative consequences going forward, even if she never serves a day in jail.
So my concerns are not moral. Whatever happens to you in the next lifetime, the consequences in this one are bad enough.