I am confused now but that’s not unusual.

Ages do vary in censuses but the Richard you refer to is 72yrs in 1911 which would give a birth year of 1839.
In 1901 (the one you mention as born c1828) he is 60 yrs o,d - b abt 1840.
As far as I can see, Briska is not a Belmullet township although there are Shevelin (variations) around that part of Mayo. Briska is closer to Bangor Erris.
I have visited the area but I am sure that someone with better knowledge could help.
If the Briska families are not yours, where is your family in 1901? - Sorry, just read your message again. Back on track, I think.