Mutual consent filed, wife asking huge amount as alimony

My son was married 5 years back. From last 5 years there have been multiple times when his wife left the home for no reason on small petty issues.They both stayed separtely and not with any one from in-laws family. My daughert in law is also working ina good firm My son took my daughter in law to multiple places outside India too when he went abroad for his work related things. Thier relation did not improve and from last 1 year my daughter in law is staying sepearately. We tried multiple times to get her back but it did not work. Finally it was agreed between the families to file a mutual consent divorce as things did not seem to change. She was not ready to stay with my son. The amount they claimed as alimony was very very high . We agreed to it that day under severe mental pressure but now i feel really sad as my son has to sell off his property, give away his savings and even borrow the money to give it to her. Please advise what can be done with reagrds to the same. I doubt that their might be something fishy and she might have something planned Please advise on the same