Worse molt of his life

Is it normal for cockatiels to be molting so badly right now? This is by far the worst molt I have ever seen in his life. He is about 4. I got him when he was 1. He unfortunately will not let me preen him. It doesn’t look like he’s plucking any feathers as all of them when they come out don’t have any blood or anything. I feel so bad for him.