He wasn't money laundering, just using his own legal money for HODL,
while he didn't want to do KYC.
I'm no sure if you're asking why he would want to not submit kyc. The major reason why it's not advisable is that you would the have copies of your personal document out there that can be leaked or hacked, putting your identity at risk. Privacy is something anyone would desire, especially when dealing with a cryptocurrency.
Now he is wondering whether he might get problems cashing out in the future.
He should not expect any problems based on the fact that the coins where purchased without kyc. He also has options to cash out without kyc.