Thank you for everyone who has been so considerate to take the time to reply especially since, I agree, what I have is a first world problem. Now I can speak to the customer service rep with more information and more options in mind, including potentially changing airlines, changing CX flights for a larger plane, switching seats so we would have better access to him or, if all else doesn't work, move to economy.

I've flown many a long haul flight in economy with a crying baby behind me so I am cognizant of my fellow passengers needs but my mother-in-law is old and can not travel so the only way she can see her only grandson is if we make these less than ideal trips. I'm just trying to find a solution that would make everyone the least unhappy so thank you again for all your thoughtful responses and suggestions.