Can the plaintiff sue the corp for the time that it was part of the estate which was settled w/ a release of no further lawsuits

As part of a settlement of an estate, the plaintiff signed a release not to sue me for anything up to that date. the company which he is now suing was part of that estate for 4 years with the exception of this last year when the judge ordered it be given to the 3 children. The plaintiff is now suing the company and one of his siblings. Is that allowed - Is this your question? Add additional information