miscarry advice

So me and my sister in law were pregnant a month apart. I'm 12 weeks now she is 6 weeks. she just found out that she will be having a miscarry due to no heartbeat and no growth 😔 shes been trying for so long and shes beyond broken, I'm worried this was her first pregnancy after years of trying and then going threw fertility treatment. How do I support her? I feel like everything I'm going to say to "try" and make her feel better is making it worse... shes drawing back and keeps saying she wants to just disappear.. do I just step back and let her mourn or is there something that would make it easier for her that I could do? I hate this we always talked about our pregnancies together and now I feel like I need to bottle my excitment to not upset her. what is your advice?