The dude didnt die, Seven saved him before he could, though he was unconscious. Out of admiration and respect, he made his disguise's appearance after his.

I wouldn't expect a complete stranger to have a revival power

Don't worry, that dude didn't die.. Dan/Ultraseven even save him again in that one ep. Not sure why this scene is taken out of context.

Then how was everyone else able to revive others?

Bruh in that episode we literally see that guy alive later. The entire plot of the episode is Seven working to save him.

He didn’t die but what ever happened to him after?

He work on the mine. That's the only thing I remember.

He only stole his look but Dan Moroboshi is literally the name that seven made up to blend in with the humans.

That would be the case, had he actually died, as he was in the episode this scene was from, you are taking a scene out of its context

Dan/Seven literally encounters the guy later that's why the show showed how he got his human form

and I thought Seven was pure heart in his own shows but nope

He saved the guy he copied his disguise from. Don't take an out-of-context meme at face value.