B2 visa rejected for in laws and tips needed for reapplication

My in laws went for B2 stamping and it got rejected due to not having enough property proof in India. They have two children (my wife + my brother in law) both in US currently. Consular thought that they could be potential immigrants and rejected the case.

Now I want to reapply and have few questions.

  1. Can I reapply immediately or should i wait for sometime?

  2. How can i strengthen the case for them? My in laws do not have any property at all. Can they pledge jewels and show them as property? Is there any way of showing property ownership for them? How about life insurance? They told about bank balance but the consular was not inclined to listen.

  3. My brother in law would return in couple of months to India. If I process visa after that, could that be an advantage as one of the children is in India at that time?

Are there any other ways outside above to get their case through for the next time? Any help would be greatly appreciated!