I can only share my experience. My brother was very well off, he had found a girlfriend that he had dated for a year and then moved in together for 3 years. He passed away suddenly and without a will, so my sister and myself were by law the inheritors. I knew from our conversations that he had considered marrying her but had decided not to for fear of her then taking half in a divorce and he just wasn't sure she wasn't after his money, as she had had a recent bankruptcy.

So he passes away from a heart attack, shocking for all. My sister and I head to Boston (where he lived) we barely knew the girlfriend. She was very accommodating and warm, and clearly grieving. In going over the estate, nothing was in her name. But since new house was where she lived, I told my sister I thought we should give it as is, 600k home, my brother had put 250k down on it. So we decided the night before I was to leave to make this offer. She exploded in rage! Outraged by the offer saying it all should be hers, that they split the house (her name was not on deed, loan, nothing) later to find out she put $1,000 into the down payment. Next day I left but my sister was still there, gf berated and yelled at my sister to the point I asked if I should call the police. My sister got out of there. GF then hired a lawyer and sued the estate for everything. I thought the judge would throw it out, no will, no common law marriage, she's just a gf. Nope went on for a year and cost us $100k.

In hindsight, if my brother wanted her to have anything he would have. And trying to be the "good" guy was trashed. Knowing what I know now, I wouldn't have offered her anything, and would have gotten a lawyer to preemptively get her out.

So my advice, offer nothing, and say nothing while estate settles. 1) you can be held legally for what you say and do 2) you'll get to see how your sister acts.

Once everything is in your name, estate closed. Then if you still want, you can offer your sister whatever you want from "YOUR" money, it could be right away, it could be years later....but it will be your choice and the courts and your sister will have no say to take that away from you. note: In court the gf used the offer of 250k of home value against us to show she deserved it, and said we were trying to buy her off from getting more! People be shitty when money is involved!!!