Probate!

Here’s the situation: My Mother died five years ago and my Father never did the Probate thing. He is trying to refinance his house and it seems to be an issue he can no longer avoid. She had a will that basically said it’s all his if he outlives her but somewhere in the five year span she’s been gone he threw it away. Everything they owned was either in my father’s name or both of their names and since any jointly-owned property passes automatically to the surviving joint owner, there shouldn’t be anything to question. So, besides going back in time and setting up a trust, is there another option to avoid this pointless and costly legal process? I’m not saying all probate is pointless but in this particular case it seems to be. I also realize that there’s a good chance I am completely ignorant about this subject and I’ve got it all wrong. If that’s the case, I apologize… please don’t be too mean educating me. Thanks.