It is his parents not mine
Looks like in 2020 then you did not cosign the PR application. Do you mean expression of interest? And now in 2024 is when his parents got picked in the pool and have to submit the PR application?
If this is the scenario then I would imagine what is submitted with the PR application now is what matters. A couple that has divorced between expression of interest and PR application submission will not have the spouse as a cosigner during application submission. That does not make the application ineligible if the sponsor income meets the thresholds in the last 3 years.
However, it is advisable to have the spouse as a cosigner because sometimes the application may take years to process. During that time if the sponsor has a bad year in terms of the income thresholds not being met and in case IRCC checks the income again then the application could be rejected.
Just my 2 cents. I am not an immigration related professional.