the corruption part is still up on debate, there are a lot of accusations but nothing yet went further.
every major brazillian politician faces charges of corruption, you can never know if it's true or the opposition trying to make them look bad. both situations happend already.
as for bolsonaro, some people like him because they feel that without him we would go back to far leftism and a big part of the population don't want that.
when he first appeard as presidential candidate, he sold us a lot of promises related to security, economy and others that we craved for for a long time, but he was actually stopped to do many of the things he promised by the oppositions that also got elected on the same year or the ones that was already elected earlier (we have ellections every 2 years, for different positions).
Here, the parties have to negotiate the number of 'chairs' they will give to each of the smaller parties that supported the main runner up in order to get elected. If you don't, your bills and other stuff won't get enough votes to go along. That's where he got fucked up - a lot of politicians that supported him during campaing turned their backs on him as soon as he got elected, for various reasons (mostly, his own fault), so everything he does, good or bad, gets hated on.
individually speaking, he has no decorum to act as president and is more like a living ideal than an administrator. the people that still supports him are ready to eat his shit for dinner if he says so, but the disapproval rate is increasing by the second.
Brazil's problem is not the president, it's the political system as a whole - We have hundreds of parties that makes affiliations with eachother for increasing their chances of getting spots on the government. This creates a scenario that you might be the most righteous person on earth, if you do not compromise
and go along with what the polititians already there want, you won't be able to do shit. Very often, those small-time polititians are getting richer being bribed by companies with dubious interest.
Our adminstration is separated onto 3 spheres.
-legislative: creates the laws and such
-judiciary: enforces the law and such
-adminstrative: runs the whole thing
The president is the main character of the administrative power, but he has almost similar power as to the head of the other two. He is able to decrete emergency state for instance and overthrow the other two, but that would be a hell of a coup.
He did changed the commander of the Federal Police (somewhat comparable to the FBI), some say, because they were advancing in investigating his sons. Not proved yet, albeit being extremely fishy movement.