I think you already know the answer to this - and your son certainly does! IT's the golden rule - do what works.

I'm not familiar with this guy, but his advice sounds very suspect. He may claim to be an expert, but he's never met your son, so how on earth could he know what's better for him than you do?
Sleep and settling are not the be all and end all of parenting. If things are working well and you're all happy, then it's all good! Kids learn to sleep on their own when they are ready - sometimes it's very early, sometimes it's much later on, but it is never a reflection of your parenting ability and it is not something that needs to be 'fixed', only managed in whatever way works best for you.

Try to erase everything he said from your mind