Can i be my brothers carer?

my brother has learning disabilities. I am not working at moment but am hoping to get job. I looked up about becoming his carer but found that if I earn more than �95 i cant become his carer. Does anybody understand what this is about. As I would think that as long as you care for them for 35hrs per week you would qualify. Why does it penalise you if you work. On the DLA website it says you can even care just at weekends for the 35hrs and still qualify.