Is any of this illegal?

Ok, so my boss is a very well off handicapped man, who I work for in his home, I have been working their for like 2 years or so. I have a co-worker who takes care of my boss during the night, and he lives with my boss. My boss buys his food, pays his bills,car insurance, attorney fee's, and he doesn't pay rent or electricity or any bill. my boss also pays him a hand written check every week with no taxes taken out of it. My co-worker is on a local aid-program to receive assistance with doctors fee's ect. , it is based on income, which I'm almost positive he is not claiming, also my boss claims my co-worker on his taxes as a dependent, even though the co-worker is 28 years old and is of no relation to my boss. I am not sure but believe my co-worker is also receiving government assistance SSI for being unable to work, he mentioned to me numerous times that all one has to do to get SSI is to act stupid and pretend to have learning disorders or something to that effect. What really bothers me is that he screams at my boss, swears at him makes very distasteful statements about him, he has 3 pitbulls who he beats and I have seen him throw/kick them down the stairs to the basement where he lives, the dogs are now becoming violent and I have to go into the basement at times to get insulin(which my boss keeps downstairs), recently 1 of the dogs grabbed the coat sleeve of a contractor who had to get into the basement, I went to help get the dogs into another room(because my wo-worker who owns them was not there at the time) and he tried to bite me, when I told my co-worker and boss(at the same time in the same room) my co-workers smiled and said "good maybe you should call me when you want in the basement". My boss sat and said nothing, and now my co-worker used the excuse that "everyone is out to get him and try to sue him over his dogs" to build a wall in the basement and convert half of it basically into his own apartment. so yeah idea.. beat dogs... let attack co-worker... get apt? I am constantly seeing my co-worker treat my boss so badly, but my boss just doesn't seem to care. I'm very close to my boss and have had lengthly conversations about why he keeps my co-worker around or how entitled I am to safety when My co-worker smiles and laughs about his dog trying to bite me, and nothing I can say will change his mind..... so I would like to know if any of the tax stuff or anything is illegal, any help would be appreciated.