URGENT HELP NEEDED - How do I heal a stray dog who has extremely infected wounds

This stray dog moved into my house while I was away, he's got these huge gaping holes which smell rancid. He's in a bad state the poor thing.

I'm in a village in the jungle, getting him to a vet is complicated so I need to help him myself. I never done this before, any advice would be much, much appreciated.

I have alcohol, peroxide and antibiotic/antifungal/anti inflammatory ointment. How can I hold him down to apply the alcohol, it's gonna sting like crazy. He has a gaping wound on the back of his neck so I can't ask someone to get him in a headlock.

I can maybe get him to eat food with antibiotic tablets, is this a good idea? Could I cure him completely like this, or do I need to sterilise the wounds with alcohol and drain the puss?

What about an antibiotic injection. Could I do an intermuscular injection? With humans, injecting in the ass is the easiest way, is the same with dogs? Could the dog heal completely like this? Unfortunately these wounds are in areas he can't lick so he has no way to clean them himself.

Could I tranquilize the dog? With tablets, an injection, another method?