Let me welcome you to TAI
Regarding your question - Is your dad comfortable driving a SUV/MUV ? I would prefer you to buy one of those big ones instead of a sedan because you have mentioned clearly in your first post - 'It will be used on State Highways(2 Lane Metalled) and Some Potty Roads in Andhra Pradesh near Vijayawada.'
Per my personal experience of driving around Hyderabad - The roads are either butter smooth or they're PATHETIC !! The sedans which can withhold with those kinda roads are rare these days and you will frequently have small niggles and rattles. If you can live with that, go straight ahead with a sedan.
If your father can drive a big one, try a Safari, Scorpio you anyway have and Xylo I won't suggest at any cost. Its the worst in that segment....be it handling, ride comfort etc. I would rather vouch for a New Bolero anyday over Xylo(infact over Safari/Scorpio too for those roads). Safari is good looking as compared to Bolero and these two are the ones which can handle anything that comes in their way.
If it has to be a Sedan and you need to drive on those roads, go for a FIAT(Linea) or a FORD(Fiesta Classic). Currently these guys are good in this segment to handle that kinda abuse. I have an extensive personal experience with Fiesta. It has much more capabilities than portrayed/thought of. I would not comment on Rapid/Vento as I do not have experience with them, please avoid SX4 at all costs, not at all a good handler and worth that much money.
Good Luck and keep us posted