i have to agree with thegreyone, at least in parts.
personally i cant see dumb-as-a-door willing to clean up his mess, or help others in that aspect.
if i remember correctly, its even mentioned in canon that dumb and grindelwald were friends and had a common theory, but grindelwald chose the path of violence, which caused the break up.
so cleaning up would mean punishing purebloods, which goes against dumbs worldview, and he'll have none of that as long as (im)possible.
as i said at the beginning, for the rest i agree with thegreyone, but adding to that:
FINALLY SOMEONE WHO KNOWS HIS ENGLISH
(and no, my native language is german, but the butchering of the english language in FF hurts, and i believe i'm not the only one who quits reading a story because of an error-induced headache)