Marriage without divorce

I am a divorcee lady. I am planning to marry a divorcee person. In his previous marriage, just 4 days after the marriage due to various issues, they have decided to seperate. The marriage was not consumated. Hence, both the parties have compromised and written a notarised document "Mutual Compromise and settlement Deed - ( in lieu of Dissolution of Marriage) " and have seperated. They have not approached any court of law. This document has been signed by both the parties and has been notarised. Is this document enough for him to get married again to me? If not , what should be the process followed ? Now, that lady got married to a different person and she and her relatives are not at all ready to involve in this again and are not showing interest to solve/finish this. Our wellwishers are saying, as she got married again, this marriage wil be null and neednot be attended to. Is it correct ? OR Is there any way to get one-sided kind of divorce ? If it is mandatory to involve her in the divorce process , what should be our action ? If she doesnt support in the process of divorce, what should be our action?