This one is both very new and frankly potentially very compilcated. I am not a lawyer and I would strongly suggest a competent estates / wills attorney here
I see the following issues here
As far as I understand it the domain(s) would go into the Estate of the deceased
1) The need for a will and probate / or letters of adminstration
2) The jurisdiction of the deceased
3) The jurisdiction of the registrar
4) The potential for estate taxes, probate fees, deemed dispositions for tax purposes etc.
5) The valuation of the domain for tax purposes. To be blunt It would be to the financial advantage of the estate to seek domain appraisals from many a member of this fourm. But would the tax authorities accept that?
Here is a potential horror story (maybe unless you are a lawyer).
A portfolio of say 500 domains held by a US deceased with a US registrar. I will keep it simple, if you really want to mess this up the deceased will purchase the domains from a registrar in a different country through a reseller in a third country.
The average valuation of each domain is say $10,000 according to great domains, but other expert witnesses, say many a speculator in this forum would say say the domains would average say $10 a name on ebay. Both valid expert witneses in court.
Now do the math
According to the estate the domains are worth $10 x 500 = $5,000 and estate taxes are due on $5,000
But the government says no the domains are worth $5,000,000 and estate taxes are due on $5,000,000.
The matter goes into litigation, and while the lititgation is going on the domains drop. But keep in mind it is the value at the time of death.
Have fun in court...