Will the husband be sinful due to his wife's refusal to fast for a few days in Ramadan for two consecutive years, and what is the ruling on a wife who makes excuses of heat and thirst despite having no legitimate Shar'i excuse that prevents her from fasting?

A woman must make up for the days she missed in Ramadan (definition), as it is a debt upon her. It is not permissible for her to delay making up these days until the following Ramadan if she is able to do so. If she delays, she has sinned and must offer a fidyah (definition) (expiation) of feeding one poor person for each day. The husband must constantly remind his wife of Allah, for he is her guardian (qawwam) and is responsible for her obedience to her Lord, as Allah Almighty says: "O you who have believed, protect yourselves and your families from a Fire," and His saying: "Men are in charge of women by [right of] what Allah has given one over the other." If she does not respond to admonition, he should employ other corrective measures, such as boycotting her in bed and non-harmful beating.