I know how that is, i've been in that situation & know how it feels, and to be honest I wouldn't tell your parents. Unlike your situation, my parents actually were cool about it & never even wanted to put him in jail.
You have options.
Lie about who your babies father is, say he's younger & have your boyfriend play along with it.
You have to watch out for the law..For the simple fact that if you want benefits from the state, food stamps,tanif. You have to give them the babys fathers name, then they'll dna test him for child support and etc. You cant claim that he lives with you.
But if you give social services a fake name, it'll take them a few years to find it.
To keep him safe, tell social services you had a one night stand with a guy named greg & don't know his last name or where he lives, etc.
Lol see, when you get into a relationship thats illegal, there's more involved than just worrying about your parents.
These days, its not up to your parents to keep him locked up or not, its the state's decision.