Mine does the same thing. She eats soft food once a day and eats dry food throughout the day. She only uses the bathroom once or twice a day and that's when i'm gone and sleeping. She isn't as young as yours though (11 months) and she is puppy pad trained, we don't keep her caged anytime. But i do think it's normal for them to not go that much. Here is just a suggestion, maybe change his feeding time? It may make him go at an earlier time so he doesn't make a mess in his bed.
