Buy the Moto X. It fits perfectly for your Dad's needs. If you can spurlge more, get the Z ultra
moto x is good but moto may not have decent service centres in india(my friend waited one month for his moto g to get his screen replaced), for the same price, nexus 5 is also a good option,otherwise moto x is a awesome phone
z ultra lacks flash(camera flash) making it a poor phone for low light photography(obviously) otherwise a decent phone,better than samsung, lenovo or those poorly made indian brands atleast