"Is there anyone who has cemetery inscriptions in that parish or records?"
I suspect his grave is one of the many whose inscription cannot be read. There is a legible grave of an Angus McLeod, who died in 1848 aged 71. If he was your ancestor's brother (feasible, but not certain) then his father was Angus MacLeod alias MacNish bain (son of Angus), a tenant in Achunahanait; wives' names were not inserted onto the parish register till 1779