>>"A weak or sickly person, especially one morbidly concerned with his or her health." - a notch above hypochondriac.
>>
>>"Bolesnik" denotes any person while ill.
>>
>>>I'm still thinking. ;-)
>>
>>Keep it up. It needs words.
>
>Is "sick" the word everyone is struggling to find here?
Not quite suitable, as it's primarily an adjective, and "the sick" actually denotes plural. Another hand-me-down, not the real article.