You place your MAX BID that you're willing to pay, and by the time the auction ends and the "Current Bid" is lower than your MAX BID and you're the Winner, you will get the Item + REFUNDED the balance.

Therefore, you just place the maximum you're willing to pay, AND GO TO SLEEP !! You don't need to camp at the AH for the last few minutes to snipe a winning auction. If you lost the auction, why bother since you not willing to pay more than you initially bidded. Get the point yet ?

As for your brother's case, the "Current Bid" matches his "Max Bid" therefore there is no refund and he win by the "Current Bid" amount.

I bid for a bow that I'm willing to pay maximum 1m yesterday, but the "Current Bid" stopped at 525k right after I place the 1mil amount. After the auction timer ends, nobody bids higher 1m, therefore the Current Bid did not move and I am the winner, with the item and refunded 475k.

I do Inferno Act1 full act run everyday with 1~2 deaths will surely net me around 300k per run.
So approx 300~500k per day, about 3~4hours.

Or, I could use a full GF gear with 5NV about 320% GF and do a Azmodan tower nightmare run about 90k per run about 20mins per run about 300k per hour.