Statutory death registration didn’t start in Ireland till 1864 so you won’t get a death certificate for Hugh.
You haven’t said what denomination Hugh was but I’ll assume RC as most McGrogans in the later censuses appear to have been that. Few RC parishes kept burial records, and as far as I am aware Loughgall (which encompasses Charlemont) doesn’t. So unless there’s a gravestone or a mention in a local paper, there may be no record of this death other than the information you already have.
I looked in the townlands index for a townland in that area of the name “Ballysc*n” but did not find one. However McGrogan is not a common name in that county. (There are none there in the 1901 census). There is a parish of Ballyscullion which is mostly in in Co Londonderry with a small part in Co Antrim. That’s near Toomebridge. Perhaps he originated there? The 1901 census has 29 McGrogans in Creagh townland in Co Londonderry, including 2 named Hugh. (Families liked to repeat names). Creagh is in the RC parish of Ardtrea, which is next Ballyscullion. I’d be inclined to search in that general area for his origins.
