What rights and provision does my brother in law have to ask for suit for permanent injunction on the basis of above?
If he has filed a suit for permanent injunction alone then his case is not maintainable.
He has no rights in the property in any maner.
If he claims the property on the basis of his such statements mentioned by you in the above paragraph, then it becomes his duty to prove his claim and also he can only claim compensation as money in lieu property.
What should be my action for the same?
You have to challenge the case filed by him on the basis of documentary evidences in your side.
What are the provision and rights I have to present in court to claim for the rent amount for the period of 22 years they have been allowed to stay?
The rent amount can be claimed for the last 3 years alone and not for the entire 22 years period.
Does the claims made by them above hold any legal standing in the court of law?
His claim appears not to be maintainable in court of law.