I grew up without a father so my grandpa was the man who raised me, even though he wasn't always there. Everyone still tells me that we are similar both by character and looks. He died when I was in my early 20s, in a very similar way like you father. Spent a day working in the filed, went to sleep and died from a heart attack during the night. I was heartbroken, there was so may thing I did in my life at the time that I wanted him to witness as they progress and for him to be proud of me and tell me I'm doing the right thing. He would always advise me and guide me when I didn't know what to do. Took me long time to accept that he is gone. I realized I must carry on and push through with what he was always telling me to do, so once we meet again he will be there to tell me he is proud of all the work I've done and things I achieved.