yes, it is a parenthitical statement {look it up}
Therefore, because it is not improper, one may begin a sentence with "therefore."
Therefore is an adverb that means "because of that." Thus it can be used in the following possible sentences:I was ill and therefore unable to go to work.The girl was a Justin Bieber fan and therefore excited about his new CD.It was raining, and all the children therefore went inside out of the playground.
I can't do this therefore my mum plays piano
yes
His beloved dog had just died, therefore he was depressed.
I am allergic to dogs, therefore we are not getting one.
i live in a house, therefore i am not homeless.
I will therefore relate the events of our first encounter with the Sasquatch.
No it is not a complete sentence on its own. It is because there should be something before Therefore.
this is my home work, therefore I need to do it at home
she had diabetes, therefore, she could not eat sugar
this is my home work, therefore I need to do it at home