At an absolute minimum the wealthy individual should be gifting $15,000 a year (tax free to both parties) to all relatives (or any other individuals) that will be in the will.
If the wealthy person lives a long time (say 20 years plus) that avoids a _lot_ of taxes for everyone.
They probably should gift a lot more than that, because the gift is not taxed by the recipient and they can include any extra amount in their lifetime gift exemption.
Exactly. I should have added then to my suggestion in other posts for the parent(s) to sell the home while they are still alive.