You are using half-truths to make it sound like a witch hunt and all because you have an axe to grind with the company.
The company does not give a rats arse what is wrong with you - they are only interested in your ability to work. If your condition impacts your attendance that is going to come down on you for sure. I have had several operations and my during my interaction with fleet, I did not feel that they wanted to know my medical issues - they wanted to know how long I could wait for the op and how long it would take to recover(and I had to give the doctor permission to give that information to them) - all perfectly reasonable.
I know that the SK will be on my record and when the next pandemic hits, I may well be let go - that is a calculation that I have made and am comfortable with. It's a reality I am lead to believe is not unique to the Middle east.
I don't know anything about your mates case but it is third hand information and I suspect skewed to his own point of view. It is also not impossible that some over zealous interviewer may have stepped over the line but that would not be the norm and is definitely not policy.