According to this webpage, the sponsor have to pay $1205 or more to sponsor a spouse or partner; sponsor child from $170:
https://www.canada.ca/en/immigration-refugees-citizenship/services/immigrate-canada/family-sponsorship/spouse-partner-children.html
For more info...
According to "https://www.canada.ca/en/immigration-refugees-citizenship/corporate/publications-manuals/operational-bulletins-manuals/temporary-residents/visitors/three-types-visas.html", it says:
The multiple-entry visa
can still be valid if affixed in a full or complete passport or travel...
With that income, perhaps they can hire someone to take care of the cooking, cleaning, laundry, shopping, anything related to the baby (instead of the husband doing so).
If you are planning to sponsor her under the family class category, please post it here:
https://www.canadavisa.com/canada-immigration-discussion-board/forums/family-class-sponsorship.5/
So you essentially showed flags that your father didn't do well in his business, when you provided a letter of financial support along with employment letter, pay stubs, and bank balance for the last three months.. Your notarized invitation letter holds no value. I don't see any suspicious...