养病 is a separable verb-object compound (离合词) meaning 'to convalesce' or 'to recuperate from an illness'. Because the object 病 is built into the verb, you cannot attach a direct object; instead, you insert time expressions or other modifiers between 养 and 病, e.g. 养了两个月病 ('recuperated for two months'). In regular usage, you can also use it as a unit: 在家养病 ('recuperate at home').