Yeah that annoyed me too at first, but if you read the raws, you'll understand why he kinda hate daiki. It's kinda sad :(
If you look at the raws, you'll kind of get why Sawato started to treat amnesia!Daiki like that. It's not so much as him blaming the new Daiki for being sick. Mild spoiler: He was actually very happy at first when Daiki survived and wholeheartedly accepted his amnesia but then amnesia!Daiki turned out to be a jerk (only at first) and just outright raped him. Which is completely different from the old Daiki who was very considerate of Sawato's feelings.
Oh and I'm talking about the latest raws. The ones here are outdated.
The sawato and daiki story is so annoying. When Daiki's clearly trying to protect him by saying he doesn't want a repeat of what happened to him and Sawato yells back that he doesn't even remember, like WTF. Who blames someone for getting amnesia? What kind of so called love is it when you can't even stay by your loved one's side when they're obviously ill, and instead BLAME them for being sick? It's like blaming someone for getting cancer! He didn't freaking ask for it! Daiki deserves someone better and it's annoying that this story's getting so much focus from what I can see of the raws.