The spouse with the lower net income is the one who makes the claim, except for certain exceptions. They are:
a) the lower income spouse was in school
b) the lower income spouse was in hospital or bedridden for 2 weeks or more
c) the lower income spouse was in prison.
The amount that can be claimed is limited to 2/3 of the working income. In the scenario you painted, that means your wife will have a claim of $3333.33 as a deduction.
https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-re...
