I know its old now, but bellum (war) actually comes duellum - a duel. Beautiful is bellus, -a, -um, an adjective as pompeius rightly said. Consider bello, -a in Italian or belle in French.
So you have either "vita bella est" or "vita pulchra est". Pulchra probably is closer to "pretty" than beautiful, though. I'd prefer the former.
As for "my father, my friend" - if your father were Roman and you said that to him, he'd beat you senseless! Constantinus just told you to call your father a girl - not something advisable. The correct answer should be "pater meus, amicus meus" or also "Meus pater, meus amicus".
If you want to address you father directly, like, "Hello to you, my father, my friend" - you would use the vocative instead: "Bene tibi, me pater, me amice."
For your father as a direct object, like "I love my father, my friend" - you would say: "Meum patrem, meum amicum amo."
As an indirect object, such as "I give this gift to my father, my friend" - use: "Patri meo, amico meo donum do."
If it's plain old "My father, my friend" that you want - like on a coffee mug - try "Pater meus, Amicus meus."