This is really interesting how English is developing so many differences. Here in the UK, " to be sick" = vomitting; we usually say someone is ill, or becomes ill quickly, and the use of "get sick" just sounds, well, American. (Sorry guys!) What also interested me in these exchanges is the implications in using "readily" or "easily" - does it simply mean the son is ill often? Or is he a bit of a hypochondriac? Or maybe even a malingerer who is conveniently ill? As always, it's all in the context- which Duo doesn't give. It's quite fun to imagine, though .