If a spouse is sponsoring someone, will that person go through WES and Ietls? And how long will that take?

That depends on what stage spouse (who is sponsoring) is at. If he/she already has PR or COPR then no need to get WES or IELTS. Even after AOR no need to get. But before AOR other spouse needs WES and IELTS and CRS should remain in same range for which he/she got ITA.

Anjali Yadav thank you for this brilliant response. Sponsor is already a citizen.