i.e.
Sue constructed a good wife for Mary.
Sue was a good wife for Mary.
Sue turned Mary into a good wife.
In the first clause, the lexical choice of thrive adds a quality 'well' or 'vigorously' to the Process, and the circumstance on Glaxo answers the Manner: means interrogative 'what with?' (Halliday & Matthiessen (2014: 318).
The second (reversible) clause identifies a happy baby with a happy mother; it does not construe a happy baby as member of the class a happy mother.*
The third clause assigns the membership of you to the class a happy mother.
* Cf. an attributive agnate which construes a mother as a member of the class happy: