Someone on a FB garden forum told me it’s deadly nightshade which I suspected it was. It was growing all over one of my neighbor’s half alive rose bush.

No, it is not deadly nightshade. It can't be because DN is not a vine and doesn't have tomato like flowers. Many people mistakenly refer to Solanum dulcamara as Deadly Nightshade but that name actually applies to a different plant, Atropa belladonna. Your plant is possibly Solanum dulcamara, aka Bittersweet or Woody Nightshade. But you are right, that does have red berries. If you would upload a photo we could id it for you for sure.

Not sure if these are great photos. I did see 1 red berry on the vine. This are pictures of the berries & the flower as best I could. Remaining part of plant is in the trash can so can’t dig out the ones with the dark purple/black berries.

The leaves & a close up of one of the flowers.

Definitely nightshade.

Looks like Solanum dulcamara in last two shots. On this side of the Atlantic it is called bittersweet nightshade, with the name bittersweet being used for Celastrus.

Yep. That's Solanum dulcamara. Bittersweet or Woody Nightshade. Embo's post underlines the importance of using botanical names if you want to be certain what plant is under discussion.