Depends on various things.
His uncle may have agreed that the estate pay the tax not the receiver.
He may not have left a total to all beneficiaries which is above the exempt limit of �300k or whatever it is now.
The amount that goes into the taxable pot can be quite a complex calculation.
His uncle may have left most to his wife, which is exempt.
So if the amount left to all non exempt beneficiaries is less than the �300k exempt limit, then he wont have tax to pay.
More info is needed to answer this acurately, as its a complex area.