Sometimes when people are ill or ingested something they shouldn't have, they cant always rush to the proper place to puke. Also, at 8 years-old, he may have been in a slight panic over the fact he was going to puke and it ended up not in the toilet. Also, he may have been too far from the toilet to make it there in time, tried to get there but, alas, the furniture got it.

I don't have much advice other than hopefully you can grin and bare it or get used to it. If you really have trouble with it, then take a clothespin and pop it on your nose to block out the smell and hopefully you can overcome the visual aspect of it.