Is a demonstrative pronoun necessary? (Julius love his homeland)
For example when translating from English to Latin, "Julius loves his homeland," would eius be used. Therefore would the answer be "Julius eius patria amat"? or just "Julius patria amat?"
In your example, eius is a possessive pronoun, meaning his or of him. It does not mean his own, which is the possessive adjective suus, -a, -um.
So, to say Julius loves his homeland, meaning that he loves his own homeland, and not that of another person, is:
Iulius patriam suam amat.
If you were to write Iulius patriam eius amat, it would mean that Julius loves the homeland of him, i.e. of another person.
In short, any use of a demonstrative pronoun in the genitive case (eius, huius, illius) must refer to someone other than the subject of the sentence.
In your sentence, you may safely leave out the possessive word: Iulius patriam amat means Julius loves (his) homeland.
Hope this helps, and thanks for asking a Latin teacher.