Can an advocate withhold settlement funds in order to get paid? Is it legal?

My husband's sister upon discovering that her younger brother had sold her dead father's property by removing the names of my husband and his sister from the deed of the Property, filed a lawsuit, according to the advocate sometime in 2003 and included my husband as a co-complainant. She hired this advocate on contingency basis and there is no written contract. My husband was advised much later about this lawsuit against his younger brother. This advocate did not even once had any communication with him until 2015 when he instructed us to come to Mumbai as the purchaser of the house was going to make his payment which never happened and we spend almost $7,000 on that trip. But on this trip, the advocate informed us that he should be paid 18% of the amount received. We objected to the exorbitant account and still do. The younger brother died. My husband and his sister received Rs. 15/- lakhs each from the Purchaser in 2018-2019 after the Land Court in Kurla, Mumbai. My husband paid Rs. 3/-lakhs as fees to the advocate in 2019. Because this property was on ancestral land, the rest of the family members decided to sell it. In the meantime, my husband died. The new Purchaser prepared documents for me and my daughter to sign as descendants to get our share of the property. I told him that we would not sign the documents unless we receive the full amount. The advocate responded by threatening that he would hold back 50% of the funds to secure his payment of fees which I know is illegal. As, I am suspicious and do not trust either my sister-in-law or the advocate I have requested the advocate and my sister-in-law to produce copies of the cancelled checks (front and back) because I feel the advocate is taking the total amount of Rs.19/+ Lakhs from our share alone. The advocate has threatened to hold back the 50% of the funds until he is paid his fees. I know this is legal. Additionally, since he was my dead husband's advocate, I have come to know that the attorney can no longer collect his fees from the funds of his client's wife and daughter. Are this two (2) issues correct? Please advise. Is it not also not true that since my husband died, I and my daughter, are not liable for the fees.