Grief Help advice!!

My husband and I just found out today that his cousin was diagnosed with stage 4 ovarian cancer and due to some other serious health conditions she has cannot have any treatment to prolong her life, she was given six months or less to live and I don’t know how to be there for my husband. I don’t want to be in a back corner waiting to be called for support but I don’t know what to say or what to do to actually help. I haven’t been a part of his family long enough to know how they grieve or to help with any serious family matters. I want to help but I don’t know how. I’m so worried I’ll mess up and say the wrong thing 😩 please help she just turned 33 last month so we’re losing an amazing life so young.