Is the expiation for a vow (nadhr) the same as the expiation for an oath (yamin)? And how can one be released from a vow to fast Mondays and Thursdays for life after a doctor has forbidden fasting due to illness?

"Whoever is unable to fulfill his vow due to a continuous inability that is not expected to cease, then his expiation is the expiation for an oath (kaffarat yamin), according to the hadith: 'And whoever makes a vow that he cannot fulfill, its expiation is the expiation for an oath.' The expiation for an oath is: feeding ten poor persons, or clothing them, or emancipating a slave. If he is unable to do so, then fasting for three days. Some scholars have also stated the obligation of feeding one poor person for each day in addition to that."