Looks like this is the Thomas Brown death cert in sources.
a) He is widowed.
b) He is in Antrim town.
c) Age is roughly correct
d) Martha Huston (his daughter in law's mother) is in attendance.
Looking at various certs, Martha Huston appears quite often in Antrim town at births. I suspect she may be some sort of "medical" person possibly ? Midwife ? However, this is the only death cert I've found with her name appearing.