Yikes!

Pyracantha comes to mind.

It's evergreen, it grows fast, it has pretty red berries, & it's got the longest, meanest thorns I ever saw.

Depending on how much ground area there is (are we talking a 6' wide bed or a 12' wide bed, etc), he might also try some rampant roses.

Mermaid is evergreen, beautiful, grows like a maniac (it's called a "house eater"), has huge, gorgeous, fragrant, sulphur-yellow roses, & thorns like vicious fishhooks.

If he feels that armaments aren't needed, some other fast-growing roses are:
Lady Banks
once-blooming, these things grow like crazy, & they'll likely be evergreen in your area.
The buttercream yellow one has some thorns, but the white one, which is fragrant, is thornless.

There's an apartment complex near me that has a very long yellow Lady Banks hedge;
it's beautiful in the spring, & they trim it only once a year just after the flowers fade.
(If you trim it after it starts to grow, you'll cut off next year's flowers.)

Rosette de Lizy;
the books all say it grows to about 4'.
Mine hit approximately 12', & it's evergreen.

Seafoam.
A thorny, evergreen plant with small, adorable white roses, it's advertised as a groundcover in the books, but, again, mine hit about 6' tall, & Seafoam spreads nicely.

I wish you & your friend the very best.

Pfitzeriana juniper shrubs and sharp hollies that get loads of winter red berries are the best looking green walls, IMO.

Vitex agnus-castus is absolutely beautiful and grows really fast without getting unmanageably tall. It is deciduous, though. I don't know the area you have to work with, but try to consider a mix of things as opposed to a solid wall. Try pampas grass behind or in front of something deciduous. Build a little trellis and have some vines grow up it in another section. Just some ideas. :)

I second the Pyracantha! It's a beautiful plant that takes care of itself, feeds the birds, and keeps people from climbing our fence;) Also standard Burford Holly.

Thanks everyone. We are going to try a mix of pyracanthia, roses, Muhly Grass, and mounding perenials (which will be planted in the early spring).

Sounds like a good plan! Incidentally, the rose 'Old Blush' will do very well in those conditions and bloom for 11 months out of the year. I'm amazed how well it survives (after getting established) with no supplemental water. It must be because of its large roots that hold moisture. I found out how large the roots are when I dug up a plant that was about three or four years old. The roots were as big as my arm!

It's evergreen in San Antonio, easily gets over 6 ft tall and is plenty thorny. It's pink flowers would show off beautifully planted with grey foliaged Texas sage, which gets huge too.