"The aged husband is a relative."
Translation:Maritus senilis est familiaris.
It's almost true. It's not even more natural, because here, it's the copula. It's even more natural when the verb is not "to be".
To sum up:
With any verb, it's more common to have it at the end of the sentence.
With the special case of "to be" (the copula verb), it's more common to have it in the middle of the sentence (or either at the beginning).