Complex sentence: Conor, born 1928, was a partner in Kennedy Crowley, a business founded by his father, which then merged to become Stokes Kennedy Crowley accountancy firm (now KPMG).
Split into simpler sentences: Conor, born 1928, was a partner in Kennedy Crowley. This was a business founded by his father, which then merged to become Stokes Kennedy Crowley accountancy firm (now KPMG).