The method he is hitting on is called progressive gambling. It is true that for any single instance of the roll, neglecting greens, its near 50/50 change to land on one particular color. However, the odds for successive same color results decrement with each spin. The way to win, is to bet twice the money you bet on the previous round.
Round One:
bet $1 on red.
Lands on black-.........
Round Two:
bet $3 on red.
Lands on black-.........
Round Three:
bet $5
Lands on red-yey. Collect $10 dollars, you made $1.
Granted, there is a possibility to continue rolling blacks, however it is unlikely--and thats what you are betting on. The only way to lose is to lose more than half your money.