Ouch! Hope the kid has learned that breaking Daddy's toys is not condusive to a happy life...
I can't help you, unfortunately, but there was a relatively recent thread about increasing the iLiad's battery capacity, which obviously meant taking the machine apart. Might be worth trying to find that thread and asking the person involved about the tools used.
I would guess that even getting a replacement stylus isn't going to help you, because if memory serves me correctly, the iLiad disables the touch screen while the stylus is in its slot, so you're going to have to get the thing out, one way or another
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