Green card for father with a 18 years old half brother

[m1rahim]

We are US citizen, my wife is planning to apply for her father's immigration. I know he will get it immediately. But the problem is my wife has a half brother who is now 18 years old.
Should my wife submit one i130 for her father only and then once her father will be here then he will apply for his under 21 years son?
Or should my wife submit two I130 together (for father and brother)- but it will take many years for her brother but father will get it soon?
Or should my wife only apply for father but her father will be able
to bring his under 21 son automatically?

Anyone, please advice us asap. Which way will be the faster way? Thanks. We appreciate your help.

 

[newacct]

Should my wife submit one i130 for her father only and then once her father will be here then he will apply for his under 21 years son?

yes

Or should my wife submit two I130 together (for father and brother)- but it will take many years for her brother but father will get it soon?

You could do that, but there would be basically no point and a waste of money.

Or should my wife only apply for father but her father will be able
to bring his under 21 son automatically?

Nope. Parents are immediate relatives and cannot have derivatives.