SK,
Thanks for your sensible and very mature post - most guys younger than you just got the SJS (shiny jet syndrome) and jump at the opportunity without checking the facts (and T&Cs).
Please talk to your brother and you will find out that the cadet scheme is nothing else but a cost cutting mission by the bean counters. How someone with your experience can be called and invited for selection as a potential CX cadet is beyond me (besides for the reason above).
Looking at your age I presume that you will plan to have a family and a few kids at some stage and there is no way you will be able to survive financially (a captain I flew with the other day called the international cadet scheme a "financial suicide mission"); therefore please do the numbers and make a sensible decision.
Since you will be on local conditions the medical
AFAIK is the same and they are discussing some education allowance for locally employed pilots; further you will have the same provident fund as every other "B Scaler" (15.5% into a Fidelity account - you can choose how you want to invest it) and staff travel entitlements as everyone else minus possibly your annual confirmed ticket home (there are no international cadets currently working for CX - they are all in ADL atm so not much intel out there - the only non chinese cadets here are people who were born in HKG or have a HKG permanent ID card).
I do realize that working for CX is an aspiration for you as it is/was for all of us CX pilots here but unfortunately the aspiration died with the introduction of this international (cost cutting) cadet scheme. Upgrade time is 5+ years plus hence the idea of using CX as a stepping stone purely to get some widebody jet time is not very practical either.
When I joined I had similiar experience and was about the same age; if I was in your boat I - if I may - would suggest the LCC avenue in Europe and then head to the Middle East or Asia once the market picks up again.
All the best
AB