Damien didn't mean to eavesdrop, but when he reached right outside the house, he could already hear an intense discussion going on.
He already knew that Irene had a rocky relationship with both her husband and granddaughter. When it came to her husband, she didn't believe him, yet she didn't really abandon him at the same time but instead kept him here safely and even helped prolong his life.
As for Reva, Irene was doing her best to protect her to not make the same mistakes she did when it came to her daughter. However, Reva was cold to Irene for all these years, thinking it was Irene's fault her mother died. But Damien knew that even then, Reva never stopped caring about her grandmother.
He knew Irene made a lot of mistakes, but he was sure that her love for her family was true.