Brother deciding between Camry and Accord is like deciding between Corolla and Civic a person who will opt for Corolla will definitely go for Camry and vice versa.
Mark X however is in entirely different league based on Toyota flagship and oldest car Crown it was on paper competition for Mercedes W203 and BMW E46 but just on paper not in real world.
You are comparing 8th gen Accord 2008 onwards which will easily cost you north of 3.5M (same shape Atlas selling for more than 1 crore).
The 10th gen Camry 2006 onwards is much cheaper at around 2.0M.
Mark-X 250 is also worth the same 2.0M plus the 300G will cost 3.0M and above.