The wife of your wife’s father is not a mahram for you

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Check below answers in case you are looking for other related questions:
Sitting with husband’s relatives and shaking hands with them
Uncles of one’s parents are mahrams

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Related Answers:
Is it permissible for the husband’s brother to take his brother’s wife to the doctor?
Sitting with non-mahrams in complete hijab
Ruling on marrying an uncle's wife
Sitting with husband’s relatives and shaking hands with them
Uncles of one’s parents are mahrams

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