4 months sounds a long time but when losing someone so significant in our lives its not long.
Im sure he knew you were all there for him.
My dad was diagnosed with cancer, was unable to eat, he started disappearing before us, then he started to respond to treatment. Everything seemed so hopeful, then I couldn't get hold of him one morning, my sister went over to check on him and found him in the hallway, already gone. I'll never forget that phonecall. He was diagnosed then lost all within the space of around 3 months.
I found the first year difficult, then the second year brought its own challenges which surprised me. I guess I'd heard lots of the first year being difficult (all the 'firsts') and no one had really talked about the second year. It was/is an ever changing journey. As time went on I found it helped to 'accept' each emotion and go with it. So if I was sad I allowed myself to be sad,
It has definitely changed me, I'm a different 'me' in a way. Im still working on some 'things' even now
I only get occasional bad days now. I miss him daily but its a less painful missing the majority of the time. I strive to do things in memory of my dad, to make him proud.
Sending a hug
xx