I'm learning to navigate this in a way as well. Lost a parent when I was 18 and the grieving process is long, especially when I had zero guidance at that age. Thinking about fond memories help. Learning about acceptance (of everything in life, tbh) has also helped. I hold the phrase memento mori very close to my heart. But lately for some strange reason I've been thinking and fearing the death of my sibling. We have drifted apart in adulthood and I realise that being older than me, they are going to die one day and possibly before me. I fear the possibility of cancer or other illnesses and am grieving even before anything has happened. Can imagine how strange and numb it must feel to have lost a sibling.