they find out that his dad is in jail
You don't find it. There isn't a dad. T_T
How to find my baby dad
Take a blood test.
In FR/LG, you have no idea where (or who) your dad is, so you really can't find him.
To find your dad you should have a talk with your mother. There may be reasons she doesn't want you to see your dad that you don't know about. If your mother will not help you find your dad then when you are 18 and no longer a minor you can try and locate him. You could speak to your dad's relatives to find out where he is, but don't go looking for him until you discuss this with your mother.
You already met his (adoptive) dad earlier in the game. Proceed with the plot and you'll find him. As for his biological dad, nobody knows.
he did not find his dad but he did find his grandfather and did not go any where
blackmail her for anything you want get it then tell your dad
Because they don't want to be a dad.
find a different pet that your dad will let you have
You Don't