I think it's not getting that the friend who has two tokens is the same as the one you owe a token to. When you change the question to make it clearer, it responds correctly.
"My friend has two tokens and I have six, but I owe one to the same friend. There is a toy that costs 7 tokens. Can my friend and I afford to buy it?"
"My friend has two tokens and I have six, but I owe one to the same friend. There is a toy that costs 7 tokens. Can my friend and I afford to buy it?"