Does a 5 watt amp provide enough volume for an electric bass to be heard by some one just learning to play bass?

My teenage son recently bought an electric bass and 5 watt amp from a friend at school. She brought the guitar to him a couple of weeks ago, but just brought the amp today. She does not have the cable to connect the guitar to the amp. Son ran his iPod through the amp, could barely hear it, and based on that, is convinced he needs to go buy a bigger amp. I'm not sure that is a legitimate test - might be comparing apples to oranges. Ought I reasonably expect that the little 5 watt amp will provide sufficient amplification for him to be able to learn and practice on the bass to begin with?

I take his interest in learning to play bass seriously. He has been playing drums for several years, and is diligent about drum lessons and practice without pressure or reminder from me.) I think he is shaping up to be a decent percussionist, but he can not carry a tune in a bucket. (Mostly eschews all music folk, but loves Barry and Neil's shanty CD - but I can't convey to you how painful it is to listen or sing along with him, even with the CD blasting - and I would never tell him that.)    Like any teenager, he is also full of grand ideas and interests. A few of them he sticks with over time, even in the face of adversity or a slow learning curve. Other interests fall to the wayside pretty quickly.

He is also a huge gear hound.