I found Alexander's son's death registration on the Scotland's People website. This gave his parents as this couple although it wrongly lists his mother's first name as Elisabeth.
Parent:
His father was John Mutch [J13]
Relationships:
Had a relationship with Agnes Wedderburn.
Children were:
- James [J51] born 1830 - died 24 November 1900 at The Lodge, Thainstone in the parish of Kintore. Married Helen Edward Black. Married Jessie Nicholson