How did he won the appeal and still be ban sponsoring his wife and kids?
There are 2 separate things in this case.
1. The sponsorship application currently in progress. This is what may be rejected due to 177(9)(d), meaning the visa officer feels they were common-law/married at time the sponsor landed as PR as single. This results in applicant being forever excluded from being sponsored.
2. A 177(9)(d) carries an automatic assumption of misrepresentation to the sponsor, since not declaring a family member is a clear form of misrepresentation. So in some cases IRCC makes moves to open a new case to start investigating the sponsor's PR status
The poster above was referring to winning (2), meaning their PR status wasn't revoked for whatever reason, perhaps on H&C grounds. However that doesn't mean (1) is forgiven so spouse is still excluded to ever be sponsored.