Originally Posted by
9Benua
IMHO, going to canada will not reset your stay, your in-laws has to get out of North America to reset it. If they only granted stay for 6 months, they will be in violation of their stay limit. It's either they extend their stay here or reduce their stay to fit in the 6 months limit.
it seems this is correct ,
http://www.justanswer.com/immigratio...isa-month.html
you can however apply for an extension of a B1 I believe , of course the easiest would be to just stay within the 6 month limit.