Got to cull the bottom 10% every year! I wonder how many people rejoin at a later point of their career, otherwise surely these sorts of practices would be unsustainable (without hiring lots of labour from abroad?).
I lost my mum just slightly over a year ago, so I know the feeling. And all I really can say is that I'm truly sorry for your loss and that I hope you can one day look back and remember the good things. I guess that's all that one can ask for when presented with situations like these.
Another library that implements this, albeit at runtime (and optionally using MIRAI is https://docs.rs/contracts/latest/contracts/