In terms of retiring the shirt, you also have to consider who would want to wear it now anyway? I suspect players would feel uncomfortable using that number now. It's Diogo's.
For the overall situation and feeling, I think this triggers different things for different people.
For me, it's not about LFC, it's about his wife and kids, and parents. My best mate died earlier this year, suddenly and unexpected. He was also far too young. When I got the news on the day it felt like I'd been hit by a house. I was completely numb.
I sat still for a couple of hours and just could not stop thinking about his family (who were also very close friends). I had to be there, I had to see them. I went to the family home to hug them all. I needed to let them know they were not alone. I needed my mate, who had passed, to know that I would look after his family.
That's all I can think about here. Diogo's wife, his kids, his parents who have lost 2 sons. It's so sad.