by " he" do you mean Kosminski? He was always in the top 5 of " absolute most likely suspects" by Ripperologists. Some of the others were Queen Victoria's grandson, the Royal Physician to Her Majesty the Queen- Dr. Gull, Thomas Cutbush, and Montague John Druitt. IIRC, Druitt was eliminated about 5 or 10 years ago, maybe using DNA?
The Ripper and the Lizzie Borden case have always fascinated me. My grandfather was fascinated by both also. He lived a block away from us and we spent tons of time there on a daily basis each summer. He was a huge history buff. For a couple of years he was interested in French wars and Napoleon. He had numerous huge maps tacked to the living room and family room walls and used color-coded thumbtacks that showed the positions of Napoleon's armies and their opponents, including troop movements, during battles. He had similar thumbtack.color-coded maps for the American Civil War. He got mad because my grandmother made him take ALL of the maps and thumbtacks down one week because she was having the garden club meeting at their house and she wanted the house to look perfect for the other ladies in the garden club.
I am not convinced Lizzie did it. But I think that if she didn't do it, she absolutely knew who did and may even have let them in to hide in her room beforehand. There were rumors, not spoken aloud in polite 1890s uppercrust society, that Andrew Borden had fathered a son out of wedlock. At the time of the murders, that son would have been about 26 years old.