Tell him NO MORE EPIDURALS!! He's not getting sufficient pain relief to have THAT MANY EPIDURALS -- besides, there's supposed to be a limit as to how many you can have -- I didn't think you could have that many but I could be wrong.
If the epidural was giving him 6wks of relief, I'd say have them, but NOT just a couple of weeks, or just ONE week!! Besides, there are risks in these injections. There are risks with ANY injection into the spinal space. One could be scar tissue, and another could be Arachnoiditis, which is an incurable ailment which is very painful although RARE. There could be other risks too. But he should be getting more pain relief than this -- and he's not, so tell him to tell the doc no more!!! The steroids are NOT GOOD FOR THE BODY. They are harmful to the bones too.
For one thing, your son cannot expect to be pain-FREE.
He should avoid surgery at ALL COSTS. Stay as conservative as he possibly can, and use ALL conservative methods before opting for surgery. Surgery is ONLY for mechanical problems and does NOT take away pain!! After surgery, you're usually left with the same pain or worse! Also, after surgery, the levels above and below the surgery site will fail because they've had to take on more of the load -- it's called the "Domino Effect." It happens all the time. It happened both times after my surgery, and it's happened too everyone I know on these forms, and on another forum I visit -- and I'm talking about hundreds of people. Since I got a computer in 1998, I've talked to thousands of people, and it's the same with them.

And I've done TONS of research on this, and it's a very common thing to happen. Unfortunately, the doctors don't tell their patients about the "Domino Effect" before surgery. If they did, patients would be able to make better informed decisions.
Your son should take his MRI to a Neurosurgeon ONLY FOR AN OPINION and nothing else. He should NOT be pressured into surgery!!! The ONLY reason for surgery in his case would be if his spinal cord was being compressed or if he was in danger of permanent nerve damage, and from what you say it doesn't sound like it, but I'd have to read his MRI report to be sure. If you can post it, it would be helpful.
Physical therapy is best in cases like his. Many times it works great for sciatica. In fact, people who have had physical therapy have the same results as people who have had surgery -- according to latest studies!!!
I wish your son the very best! I hope you will keep us posted as to how he comes out. God bless and please take care. God bless. Hugs, Lee