Sometimes you tell the white one. You know which one I mean.. the lie. Especially if it is important to her.
THEN you find another dye type and get excited about it. Maybe she will like the idea when you are doing it together. There are many natural dyes one can use in the hair. I worked with someone that used only natural products to die her hair and she looked amazing. Plus it did not damage her hair.
Sometimes we have to find another solution and present it in such a way that will get them interested too.
I have had to just express that I don't like the dye because it isn't good for them and I don't care to breath the chemicals either. I can relate to your feelings on this subject.
I started turning a silver white color at 20. Most the women in the family are blonde so it isn't as in your face. Mine was golden light brown when younger.. darker brown with red and gold when a teenager, and now it is softer brown with gold and white sprouts . Not that you wanted to know that but some are comfortable with that, and some will fight it until the end.
What I would like to try are some good natural ones. Maybe the two of you could do that together. It might even be good bonding time. It's goddess night and sister is invited!
Have you been to this one?
Best of luck to you! I am sure you can come up with something great!