Be careful with shops. I don't trust many. Definitely not Sears - they have a reputation of being dishonest. My Dad worked there and they traded parts to get owners to try and replace things. They and other shops will also try to scare you into replacing something by either overreacting or jiggling something. Go to a shop you trust, one where you konw they are honest and are not trying to take your money to get rich off of you. My mother-in-law took her Saturn to a shop and they put a $175 starter on it for her. Well, the first thing is that a starter is probably less than $100 at Advance Auto or Auto Zone, and takes two bolts to remove, and it didn't fix the problem. She needed a new battery. Maybe that's what happened to your bf. He took it in for a different problem and they "identified" this one?
The best thing you can do is educate yourself. If you jack up the truck on that side, and turn the wheel, do you see any movement if you eye the top of the wheel as you turn it? Does the wheel/rim have any movement so that it looks out of round? Or if it's smooth, does the tire look out of round? Tires are famous for getting bubbles on them, and you'll be able to see that when you turn the tire by hand. There's also issues with bent rims/wheels that can cause a shake at certain speeds. If you balance the tires, a good tire shop can verify that for you. It could be just a balance issue. The shops put little lead weight on one side of the rim/wheel to get it to rotate smoothly. If there's something wrong with the "wheel assembly", e.g., the rotor and bearings, that's another possible, although less likely problem. It could also be alignment or even suspension/struts. You can ID those by the way the tires are wearing. Outside wear on the tire is probably alignment, uneven wear I understand is suspension. Try to find out more regarding the *reason* it's wobbling. Another thing you could try doing is have someone drive another car on a four-lane with your bf's truck and look at all four tires while he's driving and it's wobbling/rattling/shaking and see if you see one wheel/tire that's moving in an odd way more than the others.