I'm the youngest of 4 dcs, with 3 older dbs.
My df passed away a few years ago, my dm about a year and a half ago. My df left most stuff, including the house, far and away the biggest asset, to my dm. She originally wrote a will that left everything to her 4 dcs equally. However, as my 3 much older dbs all own their own (very expensive) property, and only the oldest db has a dc, who's a doctor, so not likely to be short of cash either, my dm decided to change her will, to leave the house to me, as I have 3 dcs and we still rent, and have never been able to afford to buy a place of our own, due to house prices shooting up in recent years.
I know she was very worried about our financial security. I think she also wanted to leave the house to me, as it was me and my youngest db (who is a millionaire and doesn't need the money at all) who looked after her and my df in their old age. My eldest db, who lives in the US, didn't bother to visit at all in the last decade or so, and would only agree to come if my dps agreed to pay for him to fly first class (yes, really). He never called on the phone either - she called him and spoke to him maybe twice a year.
Anyway, she made the mistake of telling db1 she wanted to change her will and he kicked off. So she changed her will instead to leaving everything to be split equally between her 4 grandchildren, assuming he'd be ok with that, as his family would still get a quarter share. But he was furious, and basically blackmailed her into changing her will back again to leave it to all 4 of her dcs equally - he told her if she didn't, he would not attend her funeral or say the prayers for the dead that are crucial in my religion.
She was incredibly upset by this - she told literally everyone, must have heard her say this hundreds of times. It's like she wanted to apologise to me for not leaving me the house, and make it clear that she wanted to leave it to me, but was too scared of my db to change her will again. She did resist when he demanded to be made an executor - that was given to db3. I should add that db2 keeps out of all this, not particularly materialistic, no dcs, financially comfortable.
Anyway, when my dm passed away, it was lockdown, so in practice it would have been very difficult for db1 to attend the funeral (not that he tried). A year later, in my religion, is the stonesetting, which is also a very important religious event. Despite having blackmailed my dm into rewriting her will or he wouldn't attend the funeral, not only did he not attend the funeral or stonesetting, which he could have attended, he couldn't even be bothered to dial in via Zoom to attend it that way. He was going on holiday somewhere else instead.
He's now finally bothered to fly with his family over to the UK - which he couldn't be bothered to do when my dm was alive, or to attend her funeral or stonesetting - to take stuff he wants from the house before it's sold.
I just heard he's wrapped up to take a picture that wasn't left in my dps' wills, it belongs jointly to me and my 3 dbs as it was left to us by my grandma. It's painted by my great-grandpa (my dm's grandpa), who my ds is named after. Again, it's something that my dm said hundreds of times she wanted me to have, knowing how important this great-grandpa is in my family. My db1 claims he should have it because he likes it and it used to hang in 'his' room (we only inherited it a decade after he moved to the US!). He has so little interest in our family history he couldn't be bothered to see his dps, or attend my dm's funeral or stonesetting.
I'm just so upset - it's not enough that he blackmailed my poor dm into changing her will, he's now walking off with precious family heirlooms that are shared by all my siblings! I've said he has no right to take it as it belongs to all of us, and his answer is basically, 'Tough, I want it. I don't to discuss it further. I'm taking it.'
He'll be flying back to the US with it in a few days and I feel like I'm being stabbed - so upset. Is there anything I can do? He's just ignoring everyone's wishes except his own. I know db3 thinks I should have the picture but will almost certainly want to avoid a family row. Db2 will likewise want to keep out of it. I'm just so angry and upset.
If anyone has any suggestions of anything I can do, or can just calm me down so I'm not hurting so much, that would be appreciated. Just can't believe anyone would behave like this. 
So upset that my dm's wishes are being ridden roughshod over again. So sad that this precious heirloom will go to the US, to people who care nothing about it, and we'll never see it again.