David Highfield certainly did have an illness which is why he had to go through surgery. Nevertheless, we do not know if it was a major surgery or a minor one Hence, it is quite difficult to say that he had an illness.
Considering his age, he might have health issues but nothing as such is known. He might be ill or perfectly healthy, his supporters must wait a little longer to find out the truth. We hope all is well with the journalist and he only had to go through a minor surgery with no health problems.