Is it obligatory to make up the days from the past four years in which the questioner did not spit out blood that came out of his mouth during sleep in Ramadan, knowing that this is his habit, and does the fatwa of Shaykh Muhammad 'Ullaysh in "Fatḥ al-'Alī al-Mālik fī al-Fiqh al-Mālikī" apply to him?

What you were doing—waking up, searching for blood, and spitting it out—is not required of you; rather, it falls under the category of waswasah (whispers/obsessive thoughts). Your fasts are valid, and you do not owe any make-up days for the past four years. You are permitted to follow the fatwa of Sheikh Muhammad 'Illaysh (the Maliki scholar) if you are certain you swallowed blood; otherwise, your fasts are valid, and you do not need to follow it.