Hello Puzzclar. (Happy New Year).

I found it really hard to ask my brother for help because he has such a different way of viewing the world to me. He knows that I have self harmed (in the last 8-9 months), when he saw my scars he responded in a way I did not anticipate. He was quite understanding and honest. He did not judge me. That was surprise to me, but telling him about it got it off my chest and he sees now what I am doing to, 'not do it'.
Firstly telling him deff helped me, it was a weight off my back.
Secondly he was honest to me without any opinion.
Thirdly he then understood me more.
Fourthly I am better for him knowing.

I dont know your sister or the 'true' details of your relationship with her. I would advise caution, and use your instinct to help guide you. It's really hard to open up to family members, that much I do know; but I was surprised with the response I got, he all of a sudden started to help me more and offer support when I needed it most.
I was surprised.

I hope you find the help and support you need irl from your sister.
I hoped this helped in any way.
tgc.
S
(p.s..I dont live with my brother, that may have made a difference)