'D'F threatening to change will after DM's death

[lazyalias]

My DM died a few months ago. Since almost immediately after she died, the subject of wills has been raised routinely by my father as a threat when he doesn't get his own way or doesn't like what has been said. I won't get into it here, but he was awful to my DM, unfaithful, abusive, and isn't capable of having proper emotions.

He has several much older children from another marriage (50s vs late 20s/30s for us). DM, DB and I didnt have/don't have much contact with them at all.

My mum owned the deeds to their house in part due to 'D'F being feckless. The joint will said that everything would be divided between me and DB due to the other siblings inheriting from their DM's side.

DM was aware she was dying and didn't make changes to the joint will as she said 'D'F would never be so awful as to change it out of spite... lol.

I am assuming there is nothing we can do, and he's free to do whatever he wants with their joint will now? It's so infuriating given that it's basically all my mother's earnings, but wondering if I should cut my losses and go NC rather than dealing with this anymore.

There is no such thing as a "joint will". They will have made mirror wills which reflect each other - he dies first she gets the lot, she dies first he gets the lot. This is very common and the sort of wills DH and I have too (although we don't have the complication of previous marriages or children).

But in essence you are right, now that your mum is no longer around, your dad is free to change his will in whatever way he wishes, assuming he's of sound mind, it's properly witnessed etc.

The best thing that should be done in these circumstances would have been for your mother to leave her estate in trust

Cut your losses.

If it’s truly a joint will (aka a mutual will) he can’t change it. They are unusual though- mirror wills are more common.

In your position, I would cut my losses.

Your father sounds like a pretty nasty piece of work and you could be doing the "please don't change your will" dance round him for years or decades. What a terrible way to live your life. And all the time he might already have cut you out of his will, and you wouldn't find out until he passed away.

Another factor is that if he owns a house and later needs to pay for care or a care home, then the house might be sold and the proceeds spent before he passes away anyway.