卧病在床: be sick abed; be confined to (one's) bed by sickness; be ill abed [in bed]; be laid up with illness; be lying ill; stay in bed; take to one's bed
卧病不起: be on one's back = be ill in bedbe on one's back(=be ill in bed)be on one’s back(=be ill in b ed)be on one’s back(=be ill in bed)