Consolidating estate of parents in declining health

Soliciting tips and input from folks who have traveled this path.

Back story: My wife’s mom is losing a battle with cancer and is not long for this world. Her dad’s health is poor, and he’ll likely end up living with us as he will not thrive on his own. My mother-in-law is a small business owner, so there’s inventory to liquidate. House needs upgrades prior to renting / selling. All money generated by consolidation will go to my father-in-law and his care, and then eventually to my wife and her brother.

My wife will do the heavy lifting on this, with minimal input from her brother. She’s savvy – money-smart and very organized – but has never done anything like this before. Are there certain procedural things she should be aware of? Should she set up a separate account for the money generated (from liquidation) and spent (home improvements) during this process? How tax liabilities from liquidation are best handled? What else am I not thinking of?

My concern is that everything be perceived as above board – which I’m certain it will be – by her brother who ultimately has a vested interest in the financial outcome of this process. The last thing we need is a petty rift in the family over money during a significant emotional stressor.

TIA

ETA: Thanks to admins for moving to MT and deleting asinine OT post