Nicholas - you'll need probate for the Father and then the executor(s) can transfer the ownership to your wife as a beneficiary -
HMLR Guide Page · HM Land Registry
The registration fee is payable under Scale 2 on the current market value of the house
As to the flat your wife and her brother can transfer the ownership from their joint names to just his -
Registering land or property with HM Land Registry: Change the registered owner name - GOV.UK
Whilst the ownership is 'his problem' your wife will still need to be involved to achieve the end result wanted
Land registration is complex, designed to protect legal and financial interests in property. There can be significant consequences for any error. Please consider seeking legal representation. Before making an application without legal representation, it is important to
consider the benefits of using a conveyancer.