Worth remembering that not all tenants are out to 'get' their landlord. We were issued with a section 21 on 6 month notice because the landlord wanted to sell. We immediately started looking for property, a mixture of our budget and family needs meant that any suitable property was being snapped up before it hit market properly. The rental market is bonkers here.
We actually got to the magic 56 days point when the council considered us at risk of homelessness and were warned that leaving voluntarily before a formal eviction notice was served by the courts (not the section 21) would mean they wouldn't help.
Then the council housing person identified that our landlord hadn't registered as a landlord (legal requirement in Wales) so our section 21 was null and void. Our 6 month clock was reset once the landlord sorted the paperwork and re-issued the section 21 legally.
This meant despite our best efforts we didn't move out until almost 10 months after originally notified because we finally found somewhere that we could actually apply for (kept losing out on shortlisting because we had children...on 3 bed properties!) which we thankfully got.
If we'd reached the second end of notice date without property we would have continued paying rent but with no alternative to move to we would have have to have stayed put because we have children to consider. I'm utterly grateful it didn't reach that point but I know we really messed up the landlords plans because they lost out on two buyers with the time it took for us to find somewhere new.
If there's a way of establishing the tenants circumstances it may be worth proceeding, but if they have more to consider than just a roof over their own head then be prepared for someone who is strapped down and hoping for the best so their family isn't made homeless.
The landlord is basically trying to sell with no tenancy void, don't make that your problem.