Rural America sucks for a lot of things, be it entertainment, jobs or ya relationships. Especially bad for any thing LGBTQ relationship wise. A lot of the folks are still 'closeted' and so finding others is definitely hard. It's not as easy as Swipe on Grindr/Tinder and have a date tonight. Relationships, even friendly ones, take a lot more effort and work in RA.

My advice would be;; stop looking for a relationship. Tell your friend to look for things to do and places to be, situations and projects to enjoy. Put themselves into the situations they can have happiness and fun. The rest will follow. Tell them to find hobbies, be it bowling, gun range, ATVing, etc... something, anything that gets them out and around other people. And then just let it flow from there. Don't give them advice about finding a partner; give them advice to be in a situation, where they can find a friend or more, later. I get the goal, but it shouldn't be the sole goal for them. Have fun, do things that involve others. Interact, follow up, and have fun. :) Tell them not to start with the idea of finding a partner or .. FWB; but finding something they enjoy doing that involves others around. Being around people and then participating and involving them, will lead to the other goal eventually.

It will take time and repeated interactions. I think I read before, it takes ~6 or 7 interactions before someone feels friendly with another. So a one off bowling event typically won't lead to a relationship or a date. Multiples, with the same people around, has a better change. Do things; not people. ;)

Your friend should drive to the nearest college town and select any non-fast food restaurant. Among the staff, they will find one gay and one guy who will sell them weed. Your friend may then choose to unite the gays from each restaurant in a coalition to bring about fully automated luxury communism. (The weed, however, is probably ditch.)

Please ask your friend to hurry.

If they can, they should relocate. There are lots of benefits to being in a metropolitan area. There are lots of downsides, too. But, coming from a conservative area in my formidable years, I was shocked at the permissiveness when I got to the Bay Area. I have no desire to leave (other than it being attached to the USA). I might relocate to another country. We'll see in November.

I'd still use the internet, there's really not many other ways in a conservative area

Going out's fine but everyone is closetted, gaydar isn't perfect

Tough situation, for sure. In the short term, the internet is a decent way to connect. (I found my people through the furry community, which has a vibrant community across every state and many countries. Many are queer, the conventions are a blast of old-school fun, and many are all-ages (if a parent or guardian tags along). Many furry communities are on Telegram, usually with state and city groups, even in very rural states. This is meant more for mid teens and up/stranger danger/YMMV, but it's how I've met tons of lovely people in new cities whenever I've moved.)

Though the Trevor Project is more geared towards helping people under 25 through tough times, they might have some sort of pen pal program, which might be good for a kid who is in a remote area.

If his family knows about him being gay and is okay with it, going to a pride event in a city is also a way to start connecting with people like him. If he has a library card, there are programs like Overdrive that can allow you to digitally borrow gay books- though this depends on your library branch. Places like Montana may have some.

Sometimes, cities nearby will have pride organizations at the city or state level. These are a good way to make a first connection to gay people within the state. If you aren't sure how to find these, look for a pride parade- these orgs tend to sponsor them and are always looking for volunteers. They also might have stuff like zoom meetings or are open to answering questions for youth.

Life can be hard as a kid. Much harder still, if one is queer. Generally, though, life gets better as you get older. If he has the means to eventually go to a university or the means to move to a bigger city when he's college-aged, I recommend it.

Edit: I also like the advice below. I remember being starving for knowledge when I first came out. But I also think you shouldn't put too fine of a point on your sexuality too. Like others have said, have fun, make friends, have some hobbies- dating can come later. Plus, the best dates happen when they evolve from an already healthy friendship anyways. :)