So I one one day am going to experience this. Sister had a kid single mother her choice. Was lucky enough to move in with my farther who is not getting any younger. My mother and him separated but all amicably ect. Anyway she has now gone almost five years now raising her daughter at his house but with no foreseeable intention of getting a job ect. It is what it is I can’t force her. But when I mentioned the topic of we should have a plan just so it’s easy for everyone she said well what do you mean? I said well what’s the plan with the property because I believe it’s 50/50 down the middle but you live there? She said well I want to stay here with my daughter. I don’t have children yet and yes I own a nice two bedroom apartment with the missus but this is a three bedroom house with massive backyards and front yards garage so wo bathrooms ect ect ect. And she just would be intent with living there forever without working again. The thing is it should just be sold but she has lived there rent and mortgage free for 5 years and she will not go easily at all as she is comfortable. What do you bloody do? Especially when it’s a significant amount of money we would both get if it just got sold. Just because I worked my arse off I shouldn’t be punished. We get along very well as well but I can see where it’s going to end up.
Bro - my inlaws are having a bigger mess than this involving a lot more money than just one property. Doesn't bother or influence me personally (we want nothing from wills etc - we're ok) but I've seen how fckd up this can get.
If your father has a will, ask him if you can get a copy for safe keeping with a lawyer. If he doesn't, tell him to get one. That way you have an argument further down the track if say for example, he gets dementia and your sister influences his thinking into rewriting one.
Reckon from your side you're trying to smooth the way and fair play. Reckon from her side its a threat. Having seen where this shit can end up, its good for your dad not to see this angst. Get your copy of the will quietly, put it with the lawyers (and keep a copy yourself) and if your sister doesn't want to debate it like an adult, then you have a pretty solid plan B up the sleeve.
It really depends how your Dad goes in his older years. He's entitled to, for example, change his mind and give the whole property to your sister. Thats his call. And obviously she may pull the line with him that you're ok and she needs help. Nothing you can do about that except be a good son.
Good luck bro - as I said b4 - I'm watching a similar issue play out and my god what a fckng mess and the only real winners are lawyers. Believe the other 2 in laws have spent more than they are worth on legals, so god help the one that loses out.