He is 25, and he plans to retire at 30, in 5 years he may save another couple thousands more. Let's put on the lower part of the "couple" spectrum and say he have 200.000, in 5 years he will have 400.000 USD. This money is enough to retire early with the 4% rule http://www.mrmoneymustache.com/2012/05/29/how-much-do-i-need...

Maybe you are assuming that he want to live in the states, with the interest of this money he could live easily in Spain, Thailand, Argentina, etc...

It can be [1]. Instead of saving 10-15% of your income, suppose you cut your expenses drastically and started saving 80% of your income. The math works out that you will be financially independent within 5-7 years and no longer have a requirement to work for money.

[1] http://earlyretirementextreme.com

Note he said a couple thousand, not a couple hundred thousand.