I had to size up two sizes for this season's suiting/outwear. Make sure you check the measurements... his size 44 fits like a normal size 40.
Feel the suiting cuts fit nobody, I sized up to 42 and 44 but both times fit was way off, but on a 40 I can't even get my arms fully through. My super skinny brother didn't fit in the suit neither in 36 or 38. It's a shame as the stuff is pretty well constructed and good for shorter people.
I'm 6'3, 41 chest and the winter version pocket sweater in Alpaca fits nice in a size L. I think it fits a bit bigger than the measurements suggest. The body is perfect length on me and the arms and shoulders are even a bit slouchy.
I've read the lightweight version of the pocket sweater fits smaller though, but if you want the normal one, go with Large.