Issue with brother in law and sister in law

You people wont learn like this.

Do one thing. Pour one bucket of water on their head daily. Do mahamastabhishekam daily wth new type of liquids and take care of your husband properly.

Mind you, you stay upstairs and not them.  All the best fighting :-))

better you go for rent to a different house and let your husband recover completely.till that time you can let your house on rent or keep it under lock and key

 Lady, I dont think you understood.  For such petty things one if goes to police station it will not only look cheap but also laughable.  When your husband is not doing well, you can ask him to be more careful as there are pranksters living below your floor.

In your case, it is better to take accomodation elsewhere as December is far and you though can go to police station to give complaint will not help in any way.

Its better to stay away from bad people.

If you go to police for water on steps thrown by BIL etc you will want to go court for anything... 

Better take replies in lighter spirit and find remedy for petty things like this yourself.

Why dont you try shouting at them and making them undestand that your husband might fall?

In either case, you better evacuate the place lock it and go, and come back when husband is feeling well.