b1 visa for my parents

[federer]

Hi,
I want my parents to visit us on our kids bithday party in May.but we dont have sufficient annual income to show in support form,as my wife does nt work at all as she take care of kids.But my in-laws are ready to give us support letter as their return is over 2 hundred thousand.so will this work if they give us support letter?My father owns property in India worth around 40 lacs.can anyone give me suggestion on this one?
thanx
inder