That's such an incredibly stressful situation to be in, and I'm glad he's been able to turn to you for some support. For some starting places, the St. Louis Pride Center has a list of housing resources in the area, and even if he can make it to the center himself, that would give him a safe place to talk to someone and get a referral to a local resource: https://www.pridestl.org/resources
. Youth in Need may also be able to help him, either by connecting him with resources or helping him plan: https://www.youthinneed.org/
. The epworth shelter is also an option, as it's youth oriented and lists itself as explicitly LGBT inclusive: https://www.epworth.org/
Would he be comfortable with you sharing the county he lives in? That would allow him a lot of privacy still, but also help us find him resources that might be a little closer to home.
As far as planning goes, I would start by looking over the steps recommended in this piece, including the section on how and what to put in his "to-go" bag: https://www.scarleteen.com/safety_plan_ ... _the_abuse
. Depending on how monitored his devices are, he can also text this resource for help safety planning: https://www.1800runaway.org/
With his fears about his brother, if he thinks his safety is at risk at home, that's a time when CPS needs to get involved. I know that can be a really intimidating prospect (and I know that CPS is far from perfect), but if his brother is in danger it's a step that will help keep him safe. If your friend doesn't feel comfortable calling it in, are there adults in his life, such as other family, teachers, counselors, etc, who he'd feel safe telling about this and asking for help from?