If you pay the minimum, perhaps he could be right if you add up the interest paid over the life of the debt. Someone tell him he doesnt have to pay the minimum. In fact, he can pretend to have a prosper loan, and pay whatever the monthly amount would be directly to his credit card.
Perhaps he has no will. A prosper loan "forces" him to pay the debt off in three years. But if he has no will, Im willing to bet his credit card balances will be right back where they are now in a yr.
The bottom line though is that it makes no sense, just as fred said