Robert Rollo, 12th of Duncrub and 4th Lord Rollo - Alexander Rollo's disconnection from his family

Do you know where Alexander Rollo was born or where he died? Do you have a source reference for him?

Thanks Neil, my apologies for not providing dates in my initial comment.
My sources are very limited, which is a concern for me as I can't accurately say the information I have is correct.

I've pulled up this information from various family trees on My Heritage:

b 1707 Perthsire, Scotland

M to Jean Mitchell....I do have a source for this, Scotland Marriages 1561-1910,
https://www.familysearch.org/ark:/61903/1:1:XTNT-2XW

d Mar 1783, Aberdeensire

Family Members Lord Robert Rollo 4th and Lady Mary Rollo of Woodside

from Geni I've pulled up the same information from other family trees. It was from a tree posted by Michelle Chamberlain, that I found "he was disconnected from his parents". I've attempted to contact her with to response.

file:///C:/Users/Owner/Documents/Family%20History/rollo/Geni%20-%20Alexander%20Rollo%20(1707-1783).html

Any searching I've done on Robert and Mary Rollo, do not list him as a child, and they show no children born the year Alexander was.

Thanks for following up with me and requesting this information,
Sue