You need to post a photo of the vine. You should be able to tell just by squeezing one the skin will come off just like most grapes. The smell should be your answer. Here in Houston they grow all over the roadsides. Mustang grapes and this is about the time they ripen.

They are growing in a pot. They are are super acidic and the seeds look like peppercorns and they are really tiny. Mustang grapes do grown in San Antonio as well especially buy the river (near the Missions) but the grapes are the size of a penny maybe a dime. I guess mine are super tiny mustang grapes.

No! Not grapes. Cissus wild ivy. . Once it gets in you yard, you will never get rid of it. It grows a big tuber type root.

Thank you Plantmaven! At least they're in pots. I'll tell my husband to get rid of them ASAP. Thanks again.

It's been growing in my yard for years as a volunterr and I rather like it. I transplanted it to where I wanted to grow a well mannered vine with no care, not even watering. With my dry rocky soil it doesn't grow fast. It's also a food source for a beautiful moth. Be aware that some people are allergic to it. Luckily, I don't seem to be one of them.

Here is a link that might be useful: Grape ivy ...

I had the same result as Roselee until my friend decided to dig it up. Now it is coming up every where she pulled up a piece of root.
So, if he wants it, just be sure not to dig into the root system.
Bless her heart, she does not know a lot about plants. Yesterday she cut a young cedar elm she thought was a hackberry. I had been cultivating that tree since it was about 1 ft. tall.