Can I use Samsung Galaxy S4 for gaming and surfing without SIM card?

So lately I've decided to have another phone and give my current galaxy s4 to my son. It is installing a MPJ extended battery so battery life doesnt matter. Any other suggestion if he is going to play games and surfing with it without calling or texting? Does it still need sim card?

Yes, you can use it without SIM card. Now a days , phones are not phone, they are actually mini PC with call facility, equally valid on Android based device. So, you can always use this mini PC without SIM card.

Let me know if you need any more information.