Lorenzo says Irv had a series of health issues because he almost never went to the doctor … admitting that when he finally did go to get a physical, he didn’t believe it when the doctors told him he was diabetic.

As we told you … Irv passed away earlier this month — about six months after he suffered a stroke partially caused by diabetes.

Gotti was open about his struggle to take insulin … though he did say he was trying to change his diet in order to take better care of himself.

Gotti’s family announced the news in a touching statement … writing, he was surrounded by friends and family when he passed and he was “leaving behind a legacy that will forever resonate in the hearts of those who knew him and the countless lives he touched.”

His funeral was held just last week … and dozens of the biggest names in hip hop and R&B — from Jay-Z and Fat Joe to Ja Rule and Ashanti — showed up to pay their respects.