Need advice, sister miscarried when we were both pregnant

I found out I was pregnant with my second child and a week later my sister found out she was pregnant with her third. My husband and I were trying but hers was a welcome surprise that no one expected. So needless to say, we were both super excited to be pregnant together! My sis and I are 6 years apart and her kids were born while I was still in college and kids were the furthest thing from my mind so we hadn't ever been in the same phase of life at the same time. 

So I had been to a couple of dr. Appt's by the time I was 12 weeks pregnant, but my sister's husband had recently changed jobs and due to insurance reasons didn't get to go to a dr. Appt until she was 11 weeks. We had already been talking about our babies for over a months at this point. Well, the day of her appointment, her husband sends out a text to the whole family to let us know that there was no heartbeat. I was devastated. The first thing I could think of was feeling guilty for being pregnant, but my parents assured me I shouldn't. My next thought was being there for my sister after her d&c to help in any way possible. Then I finished reading the message her husband had sent and he said they weren't ready to talk about it with anyone and would appreciate everyone staying away until they let us know it was ok. So I accepted that. I live next door to her and it was so hard to see their car come and go and know that I couldn't walk over and hug my sister or anything. I tried taking them some baked sweets about two weeks later, but I was met by my bro-in-law at the door and told that my sister was in the bedroom and couldn't stand to see me. So I gave them more space. It's been over two months now and I have had every emotion in the book by this point. She still hasn't spoken to anyone in the whole family except to watch her kids now and then and just small talk. I'm worried that I'm doing her a disservice staying away this long and told her husband so over text. He said it was wrong of me to tell a grieving person that they are grieving incorrectly. Which isn't what I meant exactly, just that I figure when your grieving you might not want to do what helps if it hurts you. And I'm scared that by avoiding everyone and never talking about it, she's never going to heal from this. 

Please help me know what I should do! Anyone been in a situation like this before or in my sisters' shoes?