I know it's not recommended and that it could adversely affect relatives coming back later. But does anyone know how to extend a B2 Visa passed the usual 6 months they grant you at the POE?

I've got a father in law here. I'm a US citizen and I sponsored him for my wife who is an LPR.

The USCIS site is a good place to start How do I extend my stay?

Form I-539 is used. Fee $200

I hope you have a good reason for an extension... They don't just hand them out like candy...it wouldn't look too good if he overstayed if you're trying to get him here eventually on an immigrant visa...

Yeah, kinda figured that.. Don't think it's worth the risk... or the $200