This is all I can discover, hope it helps: from http://www.wicklow.ie/heritagegenealogy/1798/rebels.html#sam

Mrs McAllister, Sam's mother, had been living in Dolphin's Barn, Dublin and came to the Glen of Imaal to the grave of her only son. She stayed some time with the Dwyer's, visiting the grave daily. It was thought she then returned to Dublin and died sometime later in a Widow's Alms House in John's Lane.