Three possibilities:
1. He is saying this because its the truth. He hasn't made up his mind because he doesn't have all the facts before him. He needs to talk to JB, his parents, and whoever else before he / they can decide on what the best alternative is given what they need to know.
It'll obviously be about maximizing the NBA money. What is the best strategy and how much can he improve the payout by coming back for another year? If the answer turns out to be little, then he'll declare for the draft. If the answer is a lot, then he may stay. (That's when how much he likes school, how badly he wants a BS or BA come into play.)
The "experts" on this subject on this board all have their opinions based on what they read or even on some expertise they have accumulated based on years of watching the NBA draft, But, I'd think MCW and family would be looking for some really high quality advice.
2. He already knows what he is going to do, but is giving this answer to dodge the question.
I'd discount the "getting the degree" part of this as a motivator. We are talking about a kid who will earn 10 or 20 years worth of typical college grad salary by going pro.