What you mean is that it should say  ' . . in the Kellers' home' :  note the position of the apostrophe [ ' ].  The reason I have made it plural  i.e. more than one Keller, is that with the article 'the', it suggests that the Kellers are a family, and not just a single person.  It could be one person, however, in which case you are correct in saying  'Keller's home'.

Again, you can say 'the Keller home' to refer to the household, and it suggests that there is more than one Keller living there.

It is rather confusing, and it doesn't really matter how you say it.

Here keller is being used as a Proper noun...suggesting that the name of the house is Keller. ...Keller's home be usedto show possession. ..It belongs to the family 

My dear friends

Thanks for all your nice comments!

I agree with Anita. We should use Keller home. "home" is not a material here so we shouldn't use a possessive adjective. We can use "Keller's house".

I came to see the answer.