At this point, it might have a lot to do with what you're willing to spend. An older piano might have more charm, and if you get a certain age depending on the name you can get a resenence that can't be compared. Shop around, check out different styles. There are so many options. If you go to a piano retailer you can ask a lot of questions and they might be able to help you mke up your mind. Usually they will have some refurbished used, or just good used along with their brand new selection.
Take your time, and make a decision that you're comfortable with, and not feel pressured into.
Think with both your head and your heart. It's an investment in your son's life, and his future. Show you love by suiting the piano to his needs and likes and wants, to the best of your ability, without going into deep debt.
Good Luck Willie!!!!!!
Broccoli