What is the ruling regarding someone who missed prayers for five years, then made up three years of them and then passed away? Will Allah hold him accountable for the remaining prayers, or will He consider his intention to make up the prayers?

Regarding the obligation to make up prayers intentionally missed, there is a difference of opinion among scholars. The preponderant view is that making them up is obligatory. Whoever has missed many prayers should make up what they can, in a manner that does not harm their body or livelihood. If someone repents sincerely and begins to make up the prayers, and then passes away, it is hoped that Allah will forgive them for what remains, because they did what they were able to do, and one who repents from a sin is like one who has no sin. Allah Almighty says: "Say, 'O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.'"