"Почему он умер?! Если б было можно увидеть его, подбежать к нему, обнять и поблагодарить его!" - Мария сказала
Translation: "Why he died. If it would have been (or just "would be"???) possible to see him, run to him, hug him and express my graditute to him" - Maria said.
I must conclude that:
(a) the word б expressed the conditional structure: would (+ have) + infinitive.
(b) the word б is a synonym of бы and they are used interchangeably.