Welcome back to the Wefugees Community and thank you for reaching out to us again.
I am not a lawyer and every case needs to be assessed individually. However, I assume to apply for a family reunification visa can be indeed quite complicated (given the fact that you are not married and your child is not German). You may consider other types of visa for him as well (work, study, trainee programme etc.). There is a Bosnian-German migration counselling office in Sarajevo where he can get support. For the contact details and more information on visa procedures (also in Bosnian langauge) you may see this website. Alternatively, you can consult a migration counselling office in Germany as well. Please let us know if you need help with finding one in your area.
In any case, please also don't hesitate to get back to with any further questions.
All the best,