According to a Wikipedia article, Kathleen was the sister of Henry (Harry) Boland, who was best man at the wedding of Con O’Donovan to Agnes Monks in 1923. Boland was shot in controversial circumstances in the Civil War, while Con and Agnes were on honeymoon. According to the same Wikipedia article, “He died several days later in St. Vincent’s Hospital. As he lay dying, he refused to give the name of his attacker to his sister, Kathleen.”
Kathleen married Sean O’Donovan, brother of Con O’Donovan. He was a Senator.