Always thought that Apple products were so user friendly
His iphone is 4 yo though, I will say he got his money worth.
But Anyway, it can, maybe, be done.
1.) Google install new apps on older iOS.There are work arounds.
2.) And if new app requires a newer iOS version, apple is almost on version 11, he got 7. Jailbreak and install older versions of apps.
3.) go to swappa and buy an iphone 5 or better, starting at 80 bucks...