At the recent TV Land Awards ceremony, the former Commodores singer revealed that dealing with Nicole's drug addiction, weight problems and brief spell in jail was highly stressful.
He is quoted as saying: "Forget about surviving 40 years in the music business, just surviving 27 years of Nicole Richie has been a struggle-and-a-half, I want to tell you. I stand here as a survivor, I want you to know, for all the parents out there."
Nicole and Good Charlotte rocker Joel Madden became parents to daughter Harlow earlier this year.
"While it may take me a moment to adjust to being called granddad, I am extremely happy and proud of Nicole and Joel," remarked Lionel at the time.