IOTL, when Oliver Cromwell passed away on September 3rd 1658, he was succeeded as Lord Protector by his eldest surviving son, Richard Cromwell. Richard, however, lacked the authority of his father, particularly when it came to dealing with the NMA, and so he was eventually forced to resign. This would ultimately pave the way for the Restoration the following year.
But what if Richard died before his father, and the Protectorate passed to Oliver's fifth child, Henry? As Lord Deputy of Ireland, he had plenty of experience in governance and also commanded respect from the army that Richard lacked.
So, if Henry Cromwell followed in his father's footsteps as Lord Protector, what would the impact be? How long would the Commonwealth last? What would become of the Stuarts? Would, upon Henry's death (if we assume the Commonwealth survives), the office of Lord Protector remain a hereditary one? If so, would Henry's heir face the same problems Richard did?