Is it okay to help your parent if they ask you for help on their living will?

Well the past 5 years I have been telling my Mom to finish her will and living will because she told me she doesn't want to go in a home and stay in her house and have me or I find a good caregiver to look after her well I said if you don't do a living will and get really sick then their is nothing I can do to stop other family members or your husband from trying to put you in an old age home my sister has already suggested it I have been taking care of my Mom for 5 years now has her caregiver I do everything shower laundry cooking cleaning appointments you name I do it. I also take care of my Step-Dad he has been cater to all his life by his Mom ex-wife and my Mom but she has Parkinson's well today the health nurse came to see my Mom and did some test and then told me outside that my Mom did poorly on the questions and drawings and has the early stage of dementia anyways I felt very sad and worried for my Mom because she is expecting me to take care of her and to make sure she doesn't end up in a home she ask me to help her with some questions on her living will about 8 months ago. Now is it illegal to help her?? Then she put it away and showed me where it would be well today she wanted to look at it now it is missing what the heck I think she missed place it or her husband move it I don't know now is it illegal to help her because I don't want to be accused of anything and I am feeling guilty about it all but that is my nature feeling guilty about everything to begin with just need some advice please if any of you have time read my other posts so you understand a little bit about me and whats going on.