In order to be a sponsor-
1. You have to have money. If you are living paycheck to paycheck, it is almost impossible for you to convince the visa officer that you will be able to support the applicant.
2. Proof of having the money (bank account statement, pay stubs, assets/properties)
3. Establish relationship (applicant's and your spouse's birth certificate, your marriage certificate)
4. Notarized affidavit of Declaration that you are going to support the applicant financially.
The question is, whether you want to-
A. get rid of the burden without pissing off your spouse ? (I kind of sensed that in your writing, but not sure)
B. genuinely help the applicant?
If A. Silently submit all documents, may be drop one or two "unintentionally", and peacefully wait for the rejection.
(I am not a heartless monster, just that I have seen enough in life)
If B. Provide proof of funds (as mentioned above) for about CAD $12000+ Tuition fee for 1st year. There can be multiple sponsors as long as they fulfill criteria 1-4.
(See, I told you, I am not a monster, just that I have seen enough in life!)