Intelligence, Irresponsibility, and ADHD?

I have read clinical descriptions of ADHD symptoms and never considered that my husband could actually have ADHD until I read some of the descriptions in this forum. He has a remarkable ability to both consume and retain everything he reads. He has an advanced degree and until recently, an executive title. He has worked in the same industry for decades with a stable employment record. I attributed his behavior to the stress of his position, and other factors in our lives, but since he lost his job - nearly a year ago now - his behavior has become more aberrant. When he is awake, he occupies his time reading internet blogs, watching television, and perhaps the most productive, reading books. I come home to a messy house, sinkful of dishes, piles of unread mail, hungry kids and pets that he is completely oblivious to. I recently discovered unpaid debts he had secreted, totaling up to six figures. He stays up late, downloading music obsessively to his IPOD. I finally gave him a set of earplugs so he would not keep the rest of us awake. At first I thought he was depressed, but after nearly a year, he's seems to have adopted a posture of semi-retirement. He becomes hostile if I ask how his day was or if he read anything interesting. If I say nothing, he thinks I am scheming against him. I tried to gently suggest options to him and put him in touch with industry professionals. I have taken extra care to not put any additional burden on him, but after reading other reader's descriptions, I'm wondering if he might have adult ADHD or if he's just having a midlife crisis? I know he has turned down offers that he deemed be inadequate. Since we were married, I noticed a change in his behavior, most markedly the inability to plan or follow through on our personal goals, arguments over silly things like movies I declined to watch because the subject matter was offensive to me, and gross financial irresponsibility. He has constantly criticized me as being too closed minded, too serious, ignorant, insensitive, and slow. My company recently selected me to lead a key new project. I had hoped he would be proud of me and instead he implied that it was only because of my physical attraction. I have tried to be patient and understanding, since I know I must maintain my income, and stability for my family, but the stress has resulted in near constant migraines and profound despair.
Is it possible for someone to be highly intelligent and what appears to be highly functional and successful in professional life with ADHD? Does maintaining that appearance take all their strength and leave nothing to their personal lives? If he is suffering from ADHD, then at least I could rationalize his callous and manic behavior, and possibly seek help.  It could also explain why he's become like a rudderless ship without the professional anchor.