US President Joe Biden, winding down an emotive visit to Ireland, broke down in tears Friday during a chance encounter with the priest who read the last rites to his late son. The Irish-American president was on a visit to the celebrated Roman Catholic pilgrimage shrine at Knock, northwestern Ireland, on the final day of a three-day tour of his ancestral homeland. The president's son Beau Biden died of brain cancer aged 46 in 2015.