I think your problem is very common and difficult to manage because it is usually well intentioned and it is of course lovely people care enough to be concerned and ‘help’ but at the same time it can be extremely frustrating, even annoying. It also uses a lot of energy - you may not think of it in those terms but it does - which you can put to far better use.
As is often the case when living with any form of chronic condition, the person who has it not only has to take on board all that means mentally, physically and emotionally but also has to be ‘director of operations’ and let people know how you want to ‘play’ it. This can be another energy stealer because diplomacy and consistency is the name of the game. So what to about it? Well this is general because you don’t give any detail but I hope something in what I write will help. If you don’t feel able to broach the matter directly, how about a letter? Totally off the top of my head so have no doubt you can do better but maybe something like this?
This is a hard letter for me to write because the last thing I want to do is hurt you. I understand you worry about me and want to help only because you care but I have to ask you to please try and understand that I need to be able to do what I can from myself. I may look awkward or be slow but that doesn’t mean I can’t manage. I am writing because I don’t know how to tell you without feeling mean and ungrateful because I know I’m lucky to have you on my side.
I promise if I need help I will ask you and be grateful for it but otherwise you must let me get on with it, or at least ask if I need help before stepping in so that I have a choice - now that would be the best way you can help me.
I’m sorry if this letter upsets you but my hope now you know is we can talk about this.
However you do it I think you need to be clear in your own head about how you want to manage your Parkinson’s and I think I would try to avoid being accusatory eg ‘you’re always taking over……’ etc and maybe there are a couple of things you don’t mind them doing for you so they can still help but on your terms. I also think you may need patience - old habits die hard.
I don’t know how much this may help but it may spark ideas that will suit you.