Svsg -

I have only read the first 12 chapters so others can give more in depth -

But in short they made him a druged up dope addict who cant sing anymore and they say how much Michael does not like him and doesnt care about him etc...

Now we know from the previous Godfathers - they ALWAYS respected Fontane and they loved him, considering he was the Godson to Vito - again the author just makes the characters the way he wanted them and he was just wrong in doing this.