The saddle looks quite low for the size of the bike. Check if the saddle is really at the right height for the rider.
Rather short seat stays and a high bar position will shift the centre of mass aft. This could give quite some trouble climbing steep sections from the saddle. You spot this immediately when it feels almost as if your front tyre is lifting of the tarmac when pushing hard.
If neither is an issue, then your bike looks perfectly fine for climbing.
After most climbs there's a descend. Check brakes, quick releases, and your headset bearings before enjoying the speed down.