Does a man's saying "my mother" or "mama" to his wife, or his intending "my children" to mean his family and his wife, fall under the category of "zihar," given that he suffers from obsessive-compulsive disorder?

Calling one's wife "Ya Ummi" (O my mother) does not constitute Dhihar. It is disliked to do so intentionally, but there is no sin if it occurred out of forgetfulness or error. The questioner should not preoccupy himself with these delusions, but rather seek help from Allah, frequently remember Him, and seek refuge in Him from Satan. He should busy himself with what benefits him in his religion and his worldly life, for neglecting these delusions leads to their disappearance, while pursuing them only increases them.