Brothers are also supposed to dress modestly at all times, not just on Jummah or Eid. There are a lot of different styles of modest clothing for men, but a simple shalwar kameez combination is comfortable and very practical for whatever activity needs to be done, and looks good on any age or size.
These pictures are from Zarinas.com
Other places with simple men’s Salwaar Kameez are:
alhannah.com
shukronline.com
You can go to the individual websites for price and size information.