Monthly expense and school fees of major kid

I'm 47 yr old lady, house wife, married since 21 years, having a recently turned 18 year old child, leaving away from husband since last 2 years, due to child's education in another city There are problems in our marriage since last 15 to 17 years atleast, no domestic violence but emotional and mental harassment was there. He has not having bond with our child as well. In short, he is failed as a husband and father. Since last 1 and half years, there is no talk with husband until unless for our financial needs. On 29th of July, 2022, he came to meet me at home, without informing me, and asked me to come and stay with him or else he will not give me any type of expenses including our child's education expense as well.. When i refuse to stay with him, he left and after that he is not picking up any of my calls or replying to my texts. He has stopped giving me money for monthly expenses, and also blocked credit card What should I do? I visited a lawyer in my city, as per him, as of now, i have to agree whatever he is asking for. Because, to file a maintenance case, i have to provide proofs of his property, salary etc, which I don't have as of now. Isn't there any provision for such cases? Isn't this a blackmailing and mental harassment? My child and I am, financially, totally dependent on him only. How can he do this? Please note: we are having our house, where were used to stay before coming to this city (for my child's education) in Pune. And he is still leaving in Pune only because his job is there.