The idea is to sell the bitcoins in India and wire him back the money from the
sales proceeds in India.
Translate: The idea is that he commits tax fraud because he will not report the sale as income. Which is about the only way this makes sense, given that instead of selling them in an Exchange anywhere worldwide he goes through the trouble of sending them to SOMEONE who will sell them (manually?) and then change the funds to USD and send those over (because somehow I doubt he will have an account in whatever currency the use in India in his US bank).
Result: Possibly jail time if they find out. Like all tax fraud. At least it gets ugly. And unless the amounts are small - I am not sure you or he are aware, but "wiring the funds" leaves a bit trace for the government to ask where the money comes from.
Simple like that.
If he gets income from the sale of bitcoin, that is income. Which is taxable or not as any other income. From which he can deduct the cost of getting the bitcoin (if he mined them for example).