When i was 18 i started paying rent. I paid 1/4 of what i earnt. If it was a quiet week (part time) then i might only pay £50 - £100 but when i was fulltime i stilled paid the same %. £200 it ended up being. Although ive always been in work, i doubt my parents would expect me pay if i didnt have a job.
What im saying is, if one has a job he should be paying his way, its far far cheaper to live at home and generally speaking most parents do a lot for their kids.
The other one, if he genuinly (sp) couldnt get a job fair enough but if hes just been lazy then well, he should be doing something atleast to help out, though he really should get a job.