As your business is quite new and you are finding your feet in the game, I would keep well clear of employing a family member. You seem to put a lot of effort into your costings and keeping a tight ship. It be harder to keep your brother under control than a normal employed driver because it be harder to sack him and he may use that to his advantage. Family & business don’t mix, you will lose either one of them.
As other people say he may have problems getting a licence. One word about blackouts and the licence authority’s will run for cover.