We recently found out my grandad has pulmonary fibrosis. We don’t currently know which stage he is but I’m already grieving. Knowing I may even have 5 years and that being the positive breaks me down. But I feel wrong for feeling this grief already, I feel like this can’t be reality
Im so so sorry i know how you feel. Not knowing how long you have left is awful the week of my Nana’s funeral ( beginning of September this year) my grandad who had dementia fell ill and it was discovered he had cancer. It has spread to two parts of the body we were not allowed to see him while he was well and happy. Two weeks ago we got the call saying he might not make it through the night ! Very very late notice but that’s what is is due to covid 
luckily I was there holding his hand when he died on Halloween. It was so so so quick. Looking back I wish I done everything possible to even just speak to him on the phone and make as many memories we could. But it wasn’t ment to be for me. Maybe you could in the time he has left. His funeral was 6 days ago. And I still don’t believe it happened.