Do people really speak Frech very well in Louisiana?

yes, in south Louisiana, in bayou country, French is the main language.  Growing up, my grandparents spoke nothing BUT French to us.  My father had to learn English but still spoke in hybrid French-English sentences.  But the dialect we speak here is more of a Canadian French blended with Creole.  Most Cajun people migrated here from Nova Scotia after being exiled by the British.  What you have today, including myself, are the descendants of these exiled people.  We are called Cajuns, which is a slang form of Acadians. And we are proud of our non-american culture.

They do not actually speak French. They speak a form of pre-revolutionary Creole, which is very difficult for French people in France to understand.   Many prefer to have it  translated into English and to translate that into French themselves.

Very few people in Louisiana speak French or "Cajun" French.  The growth of mass communications (radio, cinema, TV) in English during the 20th century saw to that. 

I am a Louisiana native and have lived in Louisiana for most of my life. 

I was in New Orleans once with a person from France. She had no trouble communicating with some of the speakers of creole French there, although there are many differences. Most of the people of French descent there now come from the Acadians, who moved south from Canada. Their version of French partly reflects the Frence of the 1600s (think of Americans speaking Shakespearean English), and partly the influences of other languages in Louisiana. 

Many there are ex-Acadians who wee kicked out of Canada.  "Cajun" is a corruption of the word Acadian, and even other French speakers have trouble understanding Acadians!   Their French changed when they went to Louisiana, and many speak a Creole, which is a bit of a mix.  Some may speak French, but, in a very local dialect for sure.

they dont speak English very well so why would French be any better

Some do and some don't.