POOR BAIRN... big MIKAhugs for him (even if it means catching his dreaded lurgies).
But seriously though, I can't see why someone would make this up, and it looks to me like he has had an infection that wasn't allowed to heal up fully for whatever reasons. If it was flu then that is horrid too and would take a few weeks to be fully recovered but pneumonia is far worse so I imagine that will take much much longer to fully recover, if in fact you do.
He could have gotten it from all the constant flying around the world, all those confined germs circulating about, probably re infecting him when his immunity is low.
He is very slim and I have noticed slim people often seem to get these illnesses more often. Maybe he needs to take much more vitamins etc to help his system along a bit. That and a good and proper holiday, it's not like his shows are all very relaxed is it, he jumps about like a mad man and you can see how much effort he puts into his singing, this is part of what makes him awesome as a performer, but we all DO care about the MIKA as a person too and would prefer a healthy MIKA to any other kind,...poor bairn...aww he needs tucking up in bed and a jolly good..............PAMPERING.