What is the ruling on one who abandoned prayer and fasting for more than twenty years, then committed to them, and died before making up what they missed?

Abandoning fasting is a major sin, and abandoning prayer is even more severe, with disagreement on whether it constitutes disbelief, though the preponderant view is that it does not. One who repents and maintains their prayers and fasts before death, it is hoped their repentance will be accepted and they will have a good ending. Missed prayers are not made up for them; rather, supplication and seeking forgiveness are offered on their behalf. As for fasting, their guardians should fast on their behalf, or pay a fidya (expiation) of feeding a poor person for each day they missed, from their estate.