This must be a strategic move as Yokhunt is already in Vietnamese inventory. They must be getting it for TOT. As for Akash, it's 60s tech that India developed 10 years ago. India can sell the TOT to Vietnam against third generation obsolete fighters.
As for Brahmos, I thought India can't produce fast enough because of nonexistent manufacturing technology. The Indian manufacturers produce missile exactly like how researchers would build them, one at a time....
You missed saying the entire Indian military is from 60s, Tejas a failure, poor country, not able to feed its poor...