Maintainence for child

Iam working woman and i have a kid with pre health condition which requires to be treated for life long. can i claim maintenance only for my child and for her health and education. i don't know his salary details he is an iit mtech graduate with 14 years of experience in it industry. will i able to get maintenance in this case? pls advice. The reason for divorce is he had deserted the girlchild because of her per health condition from 2016 and i have been single parenting her. now he needs a divorce to get married so the case have reached court with false accusations . till date not a single rupee was invested by him on child and all the expenses were born by me. now i was being threatened to sign the divorce papers for merely certain amount. father of child works for an software it company and earns a double digit package. where as my career has suffered due to single parenting and taking care of child.pls advice at least now i want to ask court to direct him to provide maintenance to the child which will provide relief to me. we were married in 2012 and girl child was born on 2014. we got separated from 2016.