Long story, sorry!
My grandparents on my mum's side have always been relatively well off. Good jobs in RAF and civil service, paid house off before they were 30 etc.
They helped my mum and stepdad out many years ago, when I was about 6, as we had our home repossessed when they ran into money troubles. Because they'd be unlikely to get a mortgage again, my grandparents offered to get a mortgage on their behalf with a 10% deposit, and my DM and SD would just have to make the repayments. It was agreed they could keep the deposit as some early inheritance (Mum would be 32, my Uncle, their only other child, got the same at the time) whenever they sold the house, plus whatever they'd put into it.
They bought a house for £60k and many years later, when planning to move to a cheaper part of the country, sold it for £120k. They requested they keep the money they made on the house, and my GPs agreed. They then bought another house in the new location for £60k, leaving them mortgage free and a good few thousand in their pockets. In that time they spent a lot of money on jewellery, new cars etc, and never so much as took my GPS out for a 'thank you' meal.
So not to drip feed, my mum would say she has never had a good relationship with them. She has always moaned about them and considered them a hindrance on her life. She can be quite nasty, my grandad had bowel cancer and so had a colostomy bag and she says she wouldn't go out for a day with him because he smells and passes wind noisily etc. She's also wildly jealous of her own brother as she believes they favour him and always have. She is all round a very toxic person
Anyway, 11 years ago my Mum became power of attorney for both my GPs. Shortly after that, her and SD decided to move to France. Despite the 'bad' relationship, she practically begged them to move with her, so she could 'look after them in their old age'. Despite being happy where they were, they sold up and moved too (making a small fortune on their home which they had lived in for a long time). DM and SD bought a farm house for €80k in France. Them and my GPs agreed that my GPs would pay to have a 'granny flat' built on the side of the house, at the cost of €80k, so there would be a 50/50 ownership of the property as a whole.
Because my DM and SD arrived in France first, the house was bought only in their name. Neither of my GPs have ever been out on the deeds, or any form of paperwork. On paper, my DM and SD own the whole property including the granny flat.
My nan became quite ill at one point and the flat was not suitable for them to live in as it was mainly upstairs. So they moved into the main house and DM and SD lived in the granny flat. Before long, nan's health deteriorated rapidly and GPs decided to move back to the UK. It was agreed between both parties that the house would be sold, and the proceeds split 50/50.
Because they put so much money into the house in France, my GPs rented back in the UK
My mum in the meantime has a 'list' of money she believes they owe her. It's exactly half for repairs to the property, bills that have been racked up (this so far seems fair) a new kitchen, wallpaper and paint for when they've redecorated, landscape gardening, a new terrace, among other things. She hasn't actually ever told them she has this list, or that she's 'charging' them, but she knocking it off the 50% she's going to give them. She has told me (but not them) that the list is so long, they now owe her money and when she sells she won't be giving anything back to them. Again, they have never been told this. I wish Mum had never told me as I hate secrets especially when they involve money!
Again to avoid drop feeding, this isn't the first time she's behaved badly with money. When GPs came back to England they brought with them a left-hand drive car. Mum bought an English car in France and for convenience, they decided to swap. DH and I actually drove over to swap them. My GPs car was a smart Picasso, 5 years old, very well looked after. The one Mum had was a clapped out Kia, 10 years old, and the passenger door didn't open from the outside. Mum insisted GPs were getting the better car. When we took it back to UK, it failed its MOT and the mechanic was amazed the tyres didn't burst on the motorway as they were like balloons. They had to have it scrapped 6 months later. Mum's Picasso is still going strong.
Also Mum came back to U.K. at one point for 6 months as they were in debt again and she needed to work (she doesn't work in France, SD does). My grandad paid for six months rent on a flat upfront plus gave her free reign of his credit card for a bit, on the understanding she'd pay him back. She never has. She is like this with money - will squirm her way out when she can. She once owed me money and promised to hand it over when she visited. She'd bought me a few jumpers, and knocked the cost off what she gave me back (without my prior permission).
Anyway, nan has now passed away, grandad is still renting and is expecting a payout once their house sells. He won't get what he put in due to a dip in the market, but he thinks he's gonna get £60k back once it sells based on the market price. Mum has instructed the estate agents to not encourage viewings as she has decided she doesn't want to sell up. GD has stipulated that if it doesn't sell before he dies, his son must get half of his. Mum has stated to me she'll refuse to agree to this when the time comes - and because my GD won't be here, there's nothing anyone can do.
Mum has also been renting out the granny flat part and not informed my GD.
If you're still reading, here's my AIBU - my GD lives near me and I see him regularly. Me and DD are a big part of his lives and he lives to see DD. We are very close to him and have a fantastic relationship. I've been through a great deal in my life too, especially my childhood, and he's a real rock for me.
He said the other week, completely at random, that DD and I will be 'taken care of' when he goes. He said he wants us to have what my mum and uncle have at least had and that he's changed his will to reflect this, as we 'deserve it after all we've been through'. He didn't say much more and I don't want to press him, I just said my thanks. I don't know how much he has, but I know he has several good pensions and bank accounts and that he obviously thinks he has around £60k coming his way at some point.
I believe Mum as his power of attorney will have been informed about the will change. She hasn't mentioned it to me if she has (we have a very difficult relationship, stemming back to the childhood issues, and aren't close).
In the last few weeks she has been absolutely desperate to make my grandad out to be mentally unwell. She is telling family (and me) stories about how he's phoned SD asking strange questions (including asking if Mum is in England or France today), getting confused, calling people by the wrong names, Imagining things and forgetting significant things. She has rang his GP with her concerns. My grandad, bar the colostomy bag, is the picture of health for an 83yo. I have never ever seen anything to worry me, and I see him all the time. My nan had dementia before she died so I know the signs to spot. He's absolutely fine. However, Mum is itching to get him in a care home (she is extremely manipulative) and has flown over twice now to look at some in another area (near my uncle, 200 miles away, not near me). I think she wants to have people around to officially affirm her 'beliefs'. She's trying to convince him to get a dementia diagnosis. She controls all his finances under the guise of 'helping' (his pension statements etc go to her address) so knows every single penny that he receives, when and whom from.
AIBU to think she's gaslighting him with the ultimate goal being that his latest will change is inadmissible due to his MH? I'm honestly not bothered about the money, I wasn't ever expecting it and DH and I do quite well, but to see my GD being gaslighted is really upsetting me. My mum would do anything for money, she sold my nan's jewellery and kept the money while my nan was still warm, and I think she's royally fucked off that she'll be getting less in his will. It's only since the will change that she's behaving this way.
So AIBU to think he's being gaslighted? DH thinks I should tell him myself that Mum doesn't intend to give a single penny of his house money back, but it would cause an epic family fall out. I've told Mum 100 times that she needs to spill the beans but she won't. I don't know what to do but every time she texts to say "Grandad rang me rambling on talking nonsense, I'm worried" I can't help but think she's lying for her own gains. I have rang him and asked "have you spoken to Mum today?" And he'll say no. I see him several times a week and I've never once noticed anything of concern re his MH. I can't express just how controlling and manipulative my mother is, I don't think I'm being paranoid.