You should be thankful that she lets you live at her place. It's her house and her money and she has all the rights to impose her own rules. Without her, where would you be now? Work, save money and get your own place. Until then, thnk her for giving you a place to stay for free.
Mark-if you know the things that get to her, then be one step ahead and get them done. Don't leave dirty dishes in the sink, do them when you're done with them and put them away. Don't leave your clothes out put them in a hamper and then wash them when you have a full load. This might not be the way you would choose to live if you had your own place, but respect her house rules, whether you agree with them or not. She is set in her ways and you are in her house. If you don't like it, then move out and support yourself. There are plenty of people around who have a medical condition and are responsible for their own care and finances. I don't think you have much room to complain here.
You can't argue with old(er) people - by the time they've gotten to the point in life where they have their own roof to sleep under and sufficient funds, they're entitled to run the place as they see fit. When you own a house you will feel the same way. And if that means the light bulb gets changed within an hour of it burning out, that's all there is to it (no matter how irrational). End game.
If your medical problem is serious and needs long-term support, perhaps you should think about planning for accommodating it instead of letting your grandmother buffer the costs. Ultimately if you want her financial support you need to abide by her wishes - no matter how "right" your position may be. I haven't known any family that doesn't operate like this.
Sounds like you have a decision: work harder to help your grandmother feel appreciated, or work harder renting a place until you can save up enough for a house of your own.
Bottom line is you are living in her house, and if you don't like it, you should move out. Probably not what you wanted to hear, but maybe supporting you is stressing her out. Have a talk with her to find out, and if things cannot improve, move out.
Mark - I do have some sympathy for you with whatever medical condition you have - but there are some REALLY simple things you can do to help this, and it seems like you still kind of have a teenager mentality of cleaning up.
Don't put dirty dishes in the sink. Put them in the dishwasher.
Don't throw dirty clothes on your bedroom floor. Put them in the hamper, or the utility room, or wherever dirty clothes belong in her house.
She probably is a bit worried that her adult grandchildren aren't self-sufficient, because in her generation (and mine, although I'm much younger than she is) adult children don't come back to roost unless they are visiting, or helping. They don't return to still be taken care of.
In your case it sounds like you have a medical condition, I don't know why your sibling is also still needing to be taken care of by an old lady.
Best wishes. I think it will go a long way if you just put your things away as you go, and don't plan to put them away the next day.
You are a grown-up and you need to act like it. At 25+ years you should NOT be living off your grandmother or taking money from her. Make your own way in the world.
And the fact that you state she has money....yup, she does as she WORKED and saved her entire life so she would retire. It is not your money, nor are you entitled to it. I think she should spend HER
money how she thinks fit. And you have no say in the matter.
Get your own place, you shoud be taking care of your grandmother, not the other way around. You are not a child, quit mooching.
It sounds like your grandmother likes to get stuff done. When you have dishes and laundry do it before you go out try to help her out ask her before you go out is it anything I can do for you before I go out? So she knows you are trying to help her . Just keep doing that and I think she will be happier cause she knows you are trying to help her.
best wishes
Rachael