Gameboy Game won't hold saves?

[SomeRandomGuy1]

I'm watching my 6 year old cousin today (his parents are out looking around at car dealerships), and he's obsessed with his little Pokemon (or whatever the heck they are) game for his gameboy. He's got the Gold version that he's trying to play, but it won't hold saves anymore for some reason. He asked me to check it out but I have no clue. If he's lucky, sometimes a "continue" option will pop up when the game starts, but when that does come up it says that the file was corrupted. Most of the time it just comes up with the New Game option (and Options menu), and even if he saves a new game and restarts the Gameboy the file won't be there). Is there any way that he can fix it or that I can fix it for him? (please! He's obsessed with this thing and even started crying when he couldn't get into it last time...)