Simplify the following text for a Grade 7 native English-speaking person.
Original: Although it is reported that his uncle Dominic was a one-time IRA chief of staff , J. Bowyer Bell states in his book , The Secret Army : The IRA 1916 ( Irish Academy Press ) , that Dominic Adams was a senior figure in the IRA of the mid-1940s .
Simplified: His uncle Dominic was a senior figure in the IRA of the mid-1940s , but not the chief of staff as some people say , .