(Question:)
Can a father marry his former daughter-in-law, that is, his son’s wife, after the son has died or after the son has divorced her?
(Answer:)
If the son dies or divorces his wife, the father cannot marry his former daughter-in-law. Doing so is forbidden, as Allah the Exalted says:
﴿وَحَلَائِلُ أَبْنَائِكُمُ الَّذِينَ مِنْ أَصْلَابِكُمْ﴾
Reference: (An-Nisa: 23)
“And the wives of your sons who are from your loins (are forbidden to you).”
Therefore, a father-in-law cannot marry his daughter-in-law under any circumstances.