As US District Superior, I do not think Fr. Rostand has the power to expel any priests. As I recall, that has to come from the SG (currently Menzingen). At least +Fellay has to approve it.
I appear to have really messed up this quoting thing. Plus, I seem to have unknowingly created a post. Anyhow, I want to comment on the above from a previous response. I agree, but moreover, I think the DS will likely say to the SG, "get this guy out of here, he is a pain." And, depending upon whom the DS is, the SG will give more or less weight to a decision on expulsion.