You will get Henry's father's name and occupation from their marriage cert which was probably in England, as it doesn't seem to have been in the IOM.

1881 census:
Henry FORSHAW Head M Male 43 England Retired Engineer Fitter
Mary A. FORSHAW Wife M Female 44 Ramsey, Isle of Man, England
William H. FORSHAW Son Male 15 Ramsey, Isle of Man, England Scholar
Margaret SUTHERLAND Mother in Law W Female 69 Ramsey, Isle of Man, England Annuitant
Jane CHRISTIAN Servant U Female 44 Ramsey, Isle of Man, England General Domestic

Source Information:
Dwelling Riversdale House
Census Place Lezayre, Isle of Man, Isle of Man
Family History Library Film 1342345
Public Records Office Reference RG11
Piece / Folio 5599 / 109
Page Number 9

[IGI] MARY ANNE SUTHERLAND Christening: 24 FEB 1836 Ramsey, Isle Of Man Father: ALEXANDER SUTHERLAND Mother: MARGARET JOUGHIN

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