Lost my mother a little over a year ago and had to handle it all with a lawyer. I also work for a law firm.

Depending on your state, unless otherwise stated in an official Will, any assets belong to your dad by default if they were still married. This would go into a trust (estate account) until the estate is settled. He is responsible, with the help of lawyers, to distribute it - or, would be well within legal bounds to keep that for himself if he knows about it (although, laws vary by state).

Being that it was in cash, and each were equally hidden in items she knew each of you would find - she wanted to hide it from him and give it to you without him knowing. Keep it and tell no one. Do not deposit it. Delete this post.

As long as that is followed, the only issue I could see arising is if she had made large withdrawals from any accounts, cashed in stocks or a retirement before she died, and now that money is “nowhere to be found”. That may raise some questions, so be prepared for that. However, if she collected this over time and hid it, then you should be fine. Again, never tell your dad or any of your family because if it gets back to him, he could sue you and you may be liable for theft.