Personally, I think being a Greek "all", it means "all" no exceptions. But I note a fine point. It does not say He healed everyone who came to Him with a disease, but that He healed all the different illnesses. So, if 20 people came, and 10 had the flu, 3 had cancer, 4 had hepetitis, and 3 had gout, it would be enough if He only healed 1 of flu, 1 of cancer, 1 of hepetitis, and 1 of gout, for a total of 4. He would have healed all the diseases, but not all the people. Somehow, I don't think that's what it means. A person wouldn't knit-pick like that. It's clear the person who wrote this was impressed by Jesus' healing everyone, and maybe he just said it wrong. But it's God who wrote it, you see, so I wonder....