Does one who abandons only the Fajr prayer while observing the other prayers become a disbeliever (kafir), according to the madhhab of Ibn Uthaymeen and Ibn Taymiyyah?

Willfully missing a single prayer until its time expires is considered a major sin, but it does not take the Muslim out of the fold of Islam. Sheikh al-Islam Ibn Taymiyyah held the view that whoever sometimes abandons prayer and sometimes performs it is not a disbeliever. Rather, he is subject to a warning, and Allah Almighty may either forgive him or punish him, and such a person is prayed over, washed, and the rulings of Islam apply to him. Sheikh Ibn Uthaymeen supported this view, clarifying that disbelief only occurs with the absolute abandonment of prayer, not with partial abandonment, citing the Prophet's (peace be upon him) saying: "Between a man and polytheism and disbelief is the abandonment of prayer," and "The covenant between us and them is prayer; whoever abandons it has disbelieved." Thus, whoever prays sometimes is a transgressor and has committed a grave matter, but he is not a disbeliever as long as he acknowledges its obligation.