And they would've been hard years,” Susan Williams told ABC News’ Amy Robach in an exclusive interview that aired today on “Good Morning America," referring to what was discovered about her husband’s physical condition after his 2014 death. WATCH: Robin Williams Found Dead at Age 63 
 
 
 
 This marks Susan's first televised interview since losing the love of her life last year, as she has remained mostly quite on the subject. "It's the best love I ever dreamed of," Susan says in this clip from her sit-down with ABC News' Amy Robach. "Robin's sobriety was intact," she wrote, "and he was brave as he struggled with his own battles of depression, anxiety as well as early stages of Parkinson's disease, which he was not yet ready to share publicly." "You don't know exactly what you're looking at.  'It Was Not Depression That Killed Robin': Susan Williams Opens up to PEOPLE About Husband's Battle with Lewy Body Dementia 
 
 When Robin Williams took his life in 2014, he left his millions of fans, family, and friends shocked and grieving – no one more so than his widow Susan Williams, who for the last year has remained mostly silent about her husband's tragic passing in an effort to uncover and study the real cause of his death.Now in one of her first interviews since losing Williams' last August, Susan shares with PEOPLE the details of the debilitating brain disease called Diffuse Lewy Body Dementia or Dementia with Lewy bodies (DLB) that took hold of Williams and the couple's harrowing ordeal to fight it. What did you do?’ And he pointed to the door and I said, ‘Did you hit your head?’ And he nodded.” 
 
 ‘I GET IT, HONEY.
– More than a year after he took his own life, Robin Williams' widow is talking about his final days. In interviews with People and Good Morning America, Susan Williams says that it was Lewy Body Dementia or DLB, an incurable brain disease commonly associated with Parkinson's, that drove her husband to take his own life, though it was not diagnosed until after his death. "It was not depression that killed Robin," she tells People. "Depression was one of let's call it 50 symptoms and it was a small one." In the year before his death, Williams had dealt with other symptoms, including anxiety and impaired movement, as the couple struggled to figure out what was going on; in his final months, the symptoms became overwhelming. "I've spent this last year trying to find out what killed Robin," Williams says. "One of the doctors said, 'Robin was very aware that he was losing his mind and there was nothing he could do about it.'" "If Robin was lucky, he would've had maybe three years left," Williams tells ABC News. "And they would've been hard years. And it's a good chance he would've been locked up." During his final months, Williams was diagnosed with the early stages of Parkinson's, and things got worse: "My best friend was sinking," she says, "just disintegrating before my eyes." "One minute, totally lucid ... and then five minutes later, he would say something that wasn't—it didn't match." During the last month of his life, "he could not" keep it together, she says, but she notes that—though he did check into rehab during his final month—he had been sober for eight years when he died. On the night before he was found dead—during a week that he was supposed to check into a facility for neurocognitive testing—his last words to her were, "Goodnight, my love. Goodnight, goodnight." (Click for more from the ABC interview or the latest on Williams' estate battle.)