Divorce by One Afflicted with Diabetes or the Like 2

Answer—and Allah is the One who grants success: Allah Most High said: "But man, against himself, will be a witness, even if he presents his excuses." [Al-Qiyāmah:14–15]. Diabetes has varying degrees; if the disease surges and overwhelms to the point that the intellect is lost and his essential cognitions—most or some—become confused, then divorce does not occur at that time, for he has entered the category of the insane. In the ḥadīth: “The pen has been lifted from three: from the child until he reaches puberty, and from the insane person until he regains his reason …,” etc.
In such a case, diabetes is a kind of insanity; indeed, it has been said: “Madness has many forms.”
This state becomes evident when the patient does not know what he is saying, does not understand what is said to him, or does not remember what he said nor what was said to him.
As for anger and its intensity—while his awareness of what he says and what is said to him remains, and while he still discerns necessary knowledge—this does not prevent the occurrence of his divorce.
Source : Min Thimār al-ʿIlm wa al-Ḥikmah vol.1