The legal way is you and your brother each to give your father and mother each $10,000/year, no gift tax for less than $10,000 per person per year.
So you can give $10,000 to your father, $10,000 to your mother each year, wihtout paying any tax. Your brother can do the same.
I am not sure the $10,000 is per person or per couple. If it's per person, you can give another $20,000 to your parents under your wife's name.