Foreigners with bicycles never learn do they ? First of all they need to understand the Thai roads before try this very risky ride.
Helmets and other protections will not save you.
Stay away from the main roads how hard can it be? Why take the chance?
Germany will not give them a hard time, so let's hope he have to stay in Thailand prison for a long time.
If he was a US national he would face a lifetime in jail. Being a German could help him , unfortunately.
I have never heard of accidents on this route for 20 years, normally very safe. Happy to hear there were no serious injuries. Could have been a lot worse.