Looks like he died the following year (on 5th December) at the age of 77 and was buried in East Greenwich, RI where his brother lived. Family plot with a large central memorial stone for Robert’s immediate family, surrounded by smaller markers for other family members, including Samuel [pics from ‘findagrave’]:
He was born 13 December 1819, so would have been 76 (not 80) when that article was published. Note that the Samuel Arnold Champlin referred to on the main memorial was Robert’s son, having the same name as his brother.