That's between you and your employer.
If I was a employer and if my employee was assassinated for doing their job, I would certainly consider a promotion and all the benefits it might bring, posthumously.
That is absurd, and done at the expense of taxpayers.
If you want to give away your money, please do, but when the government unionizes against us, and steals our money, and is looting our cities, that is an entirely different story.
This is a stupid practice of making cops a different rank if they die on duty, it is just silly, but if they are doing it to increase the already overly generous benefits, then taxpayers should put a stop to that practice immediately.