I suppose anyone with a dark mark is considered guilty until proven innocent. Even Ginny was sent to stay in some abandoned family cottage until her trial. The evidence was overwhelmingly in her favour, so it was a shorter trial than most. I think they’ve tried to put the easiest cases first. The Lestrange brothers have been sentenced to life in Azkaban, though many pushed for the Dementor’s kiss. Your father’s trial will be soon and I’m not sure the result will be any different than the fate of the others. 