For the most part this is sound advice, but there are still opportunities, even when alts are over inflated (if you can catch the right ones at the right time). BTC is on the rise again and will probably dump once it hits $20k, $25k, $30k etc. leaving lots of opportunities to grab alts. Your friend will probably lose money short term, but a few months from now, he'll still probably make a reasonable profit. I sat on my Ripple for 4 months while it stagnated, thinking I'd made a mistake, but it proved out in the end.