My child is 6 months old he lives at home with me and my parents. The child's dad is getting a solicitor to try and get to see him, but I really don't want him in my sons life. He's done nothing for my son he has never changed a nappy, he hasn't bought him anything he's never even stayed around his house. He drinks, does drugs, but now has gone into the army, he use to hit me around. I don't want my son anywhere near him. I don't want my sons life ruined like he's done to me, will he still be able 2 see him?

Honestly... probably. Because he is his son too.

Have you filed for full custody with no visitation?

Im not sure what the rules are like in your military, but in the US, he isn't doing drugs anymore if he is serving.

File for full custody and child support. Leave it up to him to go for partial custody. Write down all your concerns why you do not want him in his life.
Then if he does go for visitations ask that they give him nothing more than 3 to 6 hour SUPERVISED visitations.