How do I help my obviously unhappy missionary?

I was just curious about the book of mormon and wanted to see if the rumors about it were true. So, I ordered a book of mormon online expecting it to come in the mail, but apparently thats not how it works. I was informed that the only way I could get it is if I let some missionaries bring it by, so I reluctantly agreed.

To my shock, when they came by they were two young missionary boys. Only about 3-4 years younger than me. They asked if I could meet with them a little later that week. I didn't want to, so I told them I wouldn't really have time later in the week, but if they wanted to, we could talk right then.

We didn't really talk about religion. I asked them what the book was about and I got a summery of it, but mostly we just talked about their lives. Like, about their hobbies, what they wanted to do after the mission, and some of the crazy rules they have to follow. They seemed like normal teenage boys. The more they opened up, the more the older one seemed unhappy with being a missionary. After about an hour, they said they had to go and asked if I could meet them again. We met a second time and then on the third meeting I invited them out to eat and they gladly accepted. We talked again about life and pretty much stayed away from the religious aspect. I don't want to give too much information because I don't want to out them, but some of the things the older one said truly broke my heart. I tired to help him stay positive and he certainly seemed to appreciate feeling like a normal boy. I just wish there was more I could do for him. We didn't schedule another meeting, so I'm not sure if I'll be seeing them again, but if I do, what can I do for them? I feel insanely bad for the older one. He seemed as close to tears as I've ever seen a guy before.