IPHONE not turned on through carrier but still using Wifi?

[ares380]

Ok, so my son's father has been telling me that his phone is not in service because he can't afford the bill (he has an IPHONE) and it's been turned off for about a year now. However, he claims that he can still use his phone to connect to the internet when he's home because of his Wifi. Is this possible? I would think that, if you stopped your service with the carrier, you wouldn't be able to use the phone in that manner.

 

[bignastyid]

Wifi will still work.