Tired, frustrated and not sure what to do

So this morning me and my boyfriend had an argument. And we haven't spoken all day. Some minutes ago his father came and asked him how is he feeling. He then told him his head hurts and his joints hurt. I am upset and not sure how to act because he hasn't been feeling well all day and havent even told me. I mean I know we got in an argument but atleast you could have told me your not feeling well. And he has done this more than once. If he feels sick and we are not on good terms he will not me. I always tell him health is more important to me than anything so even if we have an argument and he doesn't feel well he should let me know. But he keeps doing the samething and I'm so tired of talking to him about it.