AT gear decisions are a bit on their head relative to Alpine.
The first decision is what type of binding to get:Tech (dynafit type, but there are several options now) or Frame (Marker Tour-again several to choose from). The tech tours much, much better than the frame. The frame will seem very familiar to an alpine binding and many folks like this. For skiing there are pros and cons to each. Tech is lower height and I feel provides a better snow feel. Frame allows elasticity that some of the tech bindings are putting in, but not yet at the same level. If your friend is heavy, skis out of balance, or likes to jump things this can matter. More info here: http://www.outdoorgearlab.com/AT-Bindings-Reviews
Boots need to fit the bindings. Boots need to fit the feet. Boots range from very alpine like with a walk mode to mountaineering like with rockered sole and wide range of motion.
Skis. Folks use all sorts of skis just like in alpine. As a first ski I would avoid the ultralight ones.
Skins. Black Diamond is the most popular. I like G3. There are also several other brands. For a first skin I would recommend synthetic or a synthetic mohair mix.
Beacon. Buy a modern, NEW, beacon that is simple.
Probe and Shovel. Do not save money here. There are some wimpy probes on the market. Get a good one. A good shovel will proves it worth.
Pack. A BC specific pack is very useful. It organizes the beacon and probe inside the pack for easy access. It has ski carry straps, I like diagonal, but A frame is the other option. And allows for at least one ice ax to be carried.
Avy Classes. Have him get educated. Not only will it give him the knowledge to understand the safety decisions that are being made, but it will also let him fit into the community as he begins his path to greater understanding in the BC.
Definitely a thumbnail sketch of the topic and each of these could expand into a multi-page thread.
What specifically are the goals of your friend? What questions do they have?
The best forum on the web for this information is TGR, but it is not like Epic.