Medical in india is not required, as by brother came last week with work visa,entered qatar

you should go thru a medical here in qatar with in 7 day after arrival, and company HR dept will process your resident permit future.

but my advice.. as you are in india now, get Police clearance certificate, degree and marriage certificate attested in indian foreign affiars, if so.. these will be usefull for family visa, and for you future step to settle in qatar.