Familia Romana CAP XII

Familia Romana, CAP XII

Aemilius avunculus vester est, id est frāter mātris.
I would have expected masc. “is” rather than neuter “id”. Am I wrong?

I’d be grateful if someone were to check the following parsing and point out any mistakes. Many thanks in advance.
My brackets!

Peditēs fortēs Rōmānī (Nom.pl) gladiōs brevēs et levēs, scūta magna et gravia (Acc.pl.) ferunt.
Peditēs (Nom.pl) gladiīs brevibus et levibus, scūtīs magnīs et gravibus (Abl.pl.) armātī sunt; equitēs (Nom.pl.) hastīs longīs et gravibus (Abl.pl.) pugnant.
Peditī fortī Rōmānō (Dat.sing.) est gladius brevis et levis, scutum magnum et grave (Nom.sing.); equitī (Dat.sing.) hasta longa et gravis (Nom.sing.) est.
Pedes (Nom.sing.) gladiō brevī et levī, scūtō magnō et gravī (Abl.sing.) armātus est.

id est is used even today (abbreviated i.e.). id refers to the concept just introduced, i.e. what being an uncle means. :wink:

Oh, of course! Many thanks bedwere. I was thinking in terms of “he is your mother’s brother,” hence the confusion. Would the old Romans not have used the abbreviation i.e. which would have saved me this embarrassment? :blush: