Difficult one, the thing is that if he is an adult who is not viewed by the state to be legally unfit to manage his own afairs then there is very little you can do to help him unless he wants to be helped.
If I was you, then I would sit him down and explain to him that he could go to prison (a very aspie unfriendly place) if he gets caught doing money laundering. I would strongly advise him to go and see a good criminal lawyer, I feel I know too little to be able to tell you what to tell him to do. A legal professional would be likely to do a better job.
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Health is a state of physical, mental and social wellbeing and not merely the absence of disease or infirmity

I am not a jigsaw, I am a free man !
Diagnosed under the DSM5 rules with autism spectrum disorder, under DSM4 psychologist said would have been AS (299.80) but I suspect that I am somewhere between 299.80 and 299.00 (Autism) under DSM4.