What are the symptoms of Lewy Bodies dementia severe stage?

My husband has been diagnosed for 8 years. He sleeps a great deal of the time. His ability to carry on a conversation is gone but he makes some correct observations, however, some of the things he says don't make any sense to me. He says and does the opposite of what he means and wants. His balance is more unsteady but he has not fallen yet. His memory is poor. He walks around in the evening searching for something but he doesn't know what it is he wants. He has apraxia at times so cannot make his body do what he wants it to. He cannot be left alone.