He gets angry when questioned about why he needs so much cash. When shown the check book he is not able to tell us why he wants this and due to his dementia has almost no memory. We cannot find a "stash" in his home. weekly needs are no more than $300 but he cashes $1200 1500 and will not tell us what he needs it for.. Does not drive and has in home caregiver/family member.
Back in the day my FIL liked to hide money in his house and kept a stash in his closet safe. He would actually demand that MIL bring him the cash to the nursing home for him to count!
Mom did have some stash that she found after the dementia set in and thought she won the lottery. So she was spending it right and left. So if you can find out where he is stashing it, or maybe buy him a safe to keep it in.
I agree with NancyH. They did survive the depression so it's just his human nature to want to keep the money with him.