He is not rich. This is a totally different circumstance, with way different cash flow scenarios. Economies of scale applies here. He needs to pay off all credit card debt. Right there, he's generating positive cash flow and earning back that 10ish percent.
He can afford to milk the HELOC and car payment, not the credit card debt.
Not sure what fund you are getting annual 15% return in, most be a very risky emerging global market fund, which is usually dicey. In fact, i'd like a link to research on a fund that has earned 15% annually over a long period. Sounds like Bernie Madoff to me. It also depends on how old he is and how long he has to play the market. If he's 25, sure, go riskier. If he's 45-50, not so much.
This is a simple problem. Pay off all credit card debt. Take the remaining and fix windows (can't have water damaging house and leading to more costly repairs). Remaining money gets put to rainy day fund and save some for when the market really corrects (which it hasn't yet) to buy funds at cheap prices. We are six months or a year from the real full on bear run. Multiple experts agree on this.