have a look at manx notebook - under personal names - Moore has
BREW, contracted from MacVriew, 'the judge's son.'

The Vriew,' now the Deemster, the Scandinavian term having superseded the Celtic, gave 'Breastlaws' to the people. He was identical with the Irish Brehon. It is possible that BREW may be contracted from MacBrugaidh, 'the farmer's son.'

BREW is a purely Manx name.

Compare (Irish) MACBREHON, now universally translated JUDGE.

McBROW [1408], McBREWE [1417], BREW [1616]. BRIEW [1648], BREW [1660].

Andreas, Lonan, Santon (vc), Ballaugh, Maughold, Lezayre, Malew, Onchan (c), elsewhere (u).