A useful road bike should have tyre clearance for 28mm + muduards (fenders), for riding on wet roads.
It should have threaded eyelets for mudguards and a rear luggage rack.
The gear ratios should be suitable for the rider's power , consider compact chainset (34/50) instead of race chainset (39/52).
Make sure it fits
Budget for lock, light, mudguards, helmet, gloves, windproof top, waterproof.
Consider stepping up a grade to Pinnacle Dolomite
4 miles is an easy distance to ride in about 20mins. You should have a backup motorbike