He would've drunk the wolfsbane potion to keep himself fighting. Else, he would've already prepared before-hand to attack the death eaters in the forbidden forest or anywhere in case he becomes one

Well, Teddy doesn't become an orphan. But I still think Tonks woul've gone and died.

How about if he hadn't drink the wolfsbane potion? And Nymphadora's still pregnant? Didn't mean to make u guys sad

Well, he would've gone out of control and started to attack everyone in sight?

He wouldn't have risked being anywhere in wolfform. Being a wherewolf is contaigous, remember? Even with the potion he wouldn't have risked being around non wherewolfs, because that is a destiny he doesn't want to pass on. At best he would've fought Greyback and then backed off. He knows what even being scratched by a wherewolf means (e.g. Bill) and that it already has an effect on people. Scratching and biting is his only defense in that form. With Dora still being pregnant, none of them would have participated, but maybe Andromeda.

Well, for starters, he’d survive. So would Tonks, and Teddy wouldn’t be an orphan. And my heart won’t be ripped out brutally.