Bit of background to give you some context. I have two much older half Sisters, same Dad, different Mums. Dad was extremely physically, emotionally and verbally abusive when we were all growing up. I went a 5 year period without any contact with him and my Mum (my Mum because she knew most of the abuse was happening and did fuck all to stop it). But have low contact with them both now.
DSIS1 has a relationship with our Dad. DSIS2 cut contact with him last year after having her first baby. Because in her words "he has always been a danger to his 3 children and I also started feeling guilty with how he treated my Mum" I respect both my Sister's decisions.
Now for the issue. DSIS2 has a good relationship with her Mum as far as I am aware. She sends her pictures of her baby. All fine. But then her Mum sends these pictures to DSIS1, who sends them to my Dad. DSIS2 does not want my Dad to have pictures of the baby. My Dad has told me this himself. So I was expected to keep it hush hush about the pictures which I felt extremely guilty about. It's all come to a head with me tonight as my Dad has been badgering me to print a picture of my Nephew off onto a hard copy. I said no and told him I didn't want to do anything behind my Sister's back. I've now messaged DSIS2 to tell her that Dad has her Sons pictures and has been asking me to print them for him. Wibu to let her know? Worried about rocking the boat and it blowing up in my face, but I hated being made to keep a secret and felt my Sister should know