if glasc mixologist dies at a battlefield and i use it to play a new unit. do the othrer units heal or does combat continue?

Yes — the other units heal first, then the Deathknell unit enters, and combat resolution continues after that.

Combat Cleanup (Rule 466.1.a.1) heals all units on the board before the Deathknell trigger resolves, so the unit you play from Glasc Mixologist arrives after the enemy is fully healed — it cannot deal damage to them "before they heal." Once the Deathknell resolves and the new unit is in play, the game determines the combat result: if both players still have units, it's "No Result" and a fresh Showdown/Combat is staged (combat effectively continues); if only one side has units, that side wins and establishes control (Conquer if not yet scored this turn).

This only works if you're the Defender (you control the battlefield) — as the Attacker, you don't control it and can't play the unit there.