Manager asking to work during the Notice Period

A teammate recently resigned. Manager knows he is looking for a job outside. He was new in the team and resigned within a month. So, no KT required. And now, the manager is asking him to work on new deliverables, create a tracker, share the ETA, mention daily progress.

He is doing the same with another guy in the team who was laid off.

I am fearing what will happen if I resign next. He is a shitty person.

What’s the worse a manager can do if one doesn’t work on new deliverables? In previous company, people used to ghost their managers. Is that still allowed?