A perfect example of a mess.My father has left his will in a similar way to what @Brendan Burgess suggests here. Except he is leaving his house to me on the condition that I pay my sibling one third of it's value within three years of his death. My only query is, how is that 'value' determined? Is it simply a matter of getting one valuation from an auctioneer as soon as possible after he has passed away? Or can the valuation be calculated anytime within those three years? Or perhaps there needs to be a minimum number of valuations obtained from different auctioneers and then take the average?
Valuation should be date of death. Good luck with that if a Celtic Tiger Scenario sees a house increase substantially in 3 years from date of death.
Interestingly you seem to be of the opinion that you can wait a full 3 years to pay out to sibling. Which no doubt will make for cosy family chats if said sibling thinks they are in dire need of a pay out in year 1.