Frequent police complaints by my brother-in-law's in-laws

Dears, I am doctor currently pursuing specialization and i am married to a doctor too. My wife's brother is also married and he went to kuwait in Oct 2018 and working there, leaving his wife with her parents, with mutual consent. He started paperwork to take his wife and son to gulf in 2020. However, because of corona, the kuwait government stopped issuing new visas from 12th March 2020. His wife and her parents are torturing and harassing him over phones because he is not taking her. However, he cant take her because kuwait government has stopped issuing visas. So, his wife and parents have approached police station and complained on me, my wife, my father-in-law and mother-in-law. Note that my father-in-law and mother-in-law live with me as they are old and need medical assistance and attention, suffering from various multiple medical issues such as diabetes, cabg, epilepsy, multiple sclerosis, paralysis, brain clots and infarctions, broken leg in 3 different places, etc. We take care of them and they are dependent on us. Also note that my brother-in-law's wife does not stay with us and never has stayed with us, for the record. So there is no interaction with us. Nevertheless, she approaches different police stations near her hometown, and complaints on us with different complaints such as attempt to rape on father-in-law, harassment and interference on my wife (her sister-in-law) and on me too. The police asks us to come to station and we explain ourselves and he finally leaves us, after he counsels the complainant. In one such encounter, she made us write that we should not interfere and theres no relation with her no matter what, even though there's any such interference. We wrote the letter and signed and submitted to the police officer in charge. Now, she has complained to police again with a fresh complaint that her in-laws are not allowing her to stay with them. Ironically, this new complaint is exactly opposite of previous complaint, and subsequent underwriting which prohibit us to interfere or interact or maintain any kind of relationship with her. So, my question is what can I do under our legal system to counter complaint and approach court of law to get rid of these unnecessary and baseless complaints against me and my wife. Heard that I cant file defamation suit against them as their complaints have not ended in FIR. If yes, then how can I avoid this nuisance, i am suffering mentally and also my wife is pregnant and I don't want her health to be affected in any way. Kindly advise please. Thank you. Regards.