Need help checking for grammar errors in these sentences

Hello,

Could anyone tell me if there are grammar errors within these statements? These are lines that I took out of my essay.

"For example, in F. Scott Fitzgerald's, The Great Gatsby, Jay Gatsby falls in love with Daisy."
Is the comma after "Fitzgerald's" necessary?

"When Gatsby invites Daisy to Nick Carraway's for tea one day, the two only speak for a short while before Gatsby urges her to visit his mansion. In his home, Daisy merely cries over Gatsby's shirts..."
Is it proper to use just "Nick Carraway's" or do I have to clarify it by saying "Nick Carraway's home" ?
In the second sentence, do I need to clarify "his home" with "Gatsby's home" ?

"In Aristotle's, On Happiness, he suggests that..."
Is the comma after "Aristotle's" necessary?

"Afterall, a great man such as Mr. Gatsby had a handful of wealth; but, he did not end happy."
I think this sentence is grammatically correct but would it be better (give more emphasis) to use a ", but" rather than the semicolon?

Thanks!
John

" "For example, in F. Scott Fitzgerald's book, The Great Gatsby, Jay Gatsby falls in love with Daisy."
  In this form yes because it gives an additional information by the way The Great Gatsby is the name of book.(or else don't use a comma)      

"When Gatsby invites Daisy to Nick Carraway's for tea one day, the two only speak for a short while before Gatsby urges her to visit his mansion. In his home, Daisy merely cries over Gatsby's shirts..."
Is it proper to use just "Nick Carraway's" or do I have to clarify it by saying "Nick Carraway's home" ?
In the second sentence, do I need to clarify "his home" with "Gatsby's home" ?
For people who have no idea about the book it would be better if you explain it and my thought is that I would think that Nick Carraway's was a restaurant or cafe.          

I think here no need to tell Gatsby's home.         

 In Aristotle's book, On Happiness, he suggests that..."
Is the comma after "Aristotle's" necessary?  In this form yes it gives additional information(or else don't use a comma) 

Afterall, a great man such as Mr. Gatsby had a handful of wealth but he didn't end up happy(I am not sure of didn't end happy)