Keep working from home until they fire you, while making contingency plans. What are they going to do if many just keep staying home while actually doing work? At the very least this will drag out the resolution of the issue much longer.
This is true if he quits too though, which I thought was the other option being considered. If he wants to just comply and keep working there then this post is unnecessary. Being fired would come much later than quitting. In the mean time he can pursue other jobs too while also calling their bluff that they'll reverse mandate like they've done before.
If you get fired from your 6 figure cushy engineering job and need that unemployment, what are you even doing..
There is nothing wrong about collecting unemployment insurance if you’re unemployed, regardless of your previous job or salary.
I don’t know where this mind worm of not using programs that were literally made for these circumstances but you are entitled to use them and should collect them.
The company pays for unemployment insurance, if they don’t want to pay their premium rates increasing they shouldn’t have fired people.
That strategy comes with a nonzero chance of having unemployment delayed (fired for cause). So if OP chooses that route, he/she better have a bulletproof reserve and a plan B and plan C if it takes longer than expected to get a new job.
I do think that this is a just strategy, though. If you give 100% of what was contracted, and your colleagues know you are all in on the success of the team, your high functioning team can outlast the winds of change from HR, easy.