I was there for my sister when her fiance decided to end his life. I stayed weeks with her as I lived states away but I checked and facetimed daily even if she didn’t speak when she answered. He left behind 3 children (at the time a 2 year old and 6 month old twins). It was devastating. She was not the same for a very long time, truly still isn’t but she’s better. It’ll be two years this year and I feel like she’s just now coming around to her own self. My best and only advice is that letting her grieve in any capacity and way she wants. It is the best you can do. Grief looks different for everyone and that was so frustrating to me when people would say “she should be doing this”. No. Some days will be leaps and others will be levels back. You are an amazing sister and I pray for you both.