"...there is a note on the record that the “father is registered in Bobruisk”. Does this mean the father was still alive at the time of his sons birth?" Is it possible that the father was both registered there and deceased? Perhaps someone can answer this question.
Similar to Shelley MItchell's post, every first born in my family except has a name that starts with B, including me. The other family's second born's name starts with B; the first born was named for the mother's deceased mother. The rest of us were named for my maternal grandmother, who died well before we were born.