The BBC's recent adaptation of the Agatha Christie novel was another in a long line of fictionalised will disputes.
Don't read any further if you want to avoid plot spoilers, but in BBC4's Modus, the murders in question were all because a son who had been disinherited from his father's will wanted to bump off the apparently favoured brother - only for the lawyers who had drafted the will to destroy it in an apparent crisis of conscience.
Had the shipping magnate father lived in England and Wales, then Marcus could have thought about a claim under the Inheritance (Provision for Family and Dependants) Act 1975 - entitled children (and others) to bring claims for "reasonable financial provision".
It is worth noting that the destruction of the will wouldn't have prevented from being "proven" i.e. relied upon. Cases of missing or inadvertently destroyed wills are surprisingly common...
Niclas’ mother had told him he was the sole heir to the Ståhl fortune, if only he could locate the fancy law firm that had the will. (Cue a scene in a law firm where the lawyers who had only just found said will in the lawyer’s grandpa’s things, where it had been gathering dust, shred it on hearing of Marcus’ death to avoid looking incompetent).