Ambien for the Elderly

I’ve watched my grandpa deteriorate lately from the use of Ambien. He’s 82 and its been months since he’s been taking ambien on and off. Last night wasn’t the first night that he fell out of his bed. I guessed that he had taken his prescribed ambien to help him with sleeping but the thing about him is that he doesn’t go straight to sleep. I kept trying to ask him how many he had consumed but he was in this like intoxicated drunk state. He must’ve taken a bunch and forgot. I was really scared because he couldn’t walk and started talking really loopy. Me and my grandma had to force him to sleep because he kept wanting to get up and do things. We finally got him to sleep. But not after drinking a lot of water. I lnow he took more than the amount he was suppose to. He couldn’t even open his eyes which scared me so much. I was wondering if taking ambien makes you dehydrated? And how long does the effects last because he is still loopy this morning but more conscience. I’ve taken all his ambien away and I don’t know what to. I’m not sure if he abusing it on purpose because this has happenend before or if he’s taking to many on accident because he doesn’t remeber. I think he. Has had suicidal thoughts before and his mood seems a lot more depressive. When he’s acting normally he never wanted to go out even when I asked him. Any insight on this would be greatly appreciated and helpful. Thanks in advance.