I've had this exact mix-up during a marathon breeding session, so here's the clear scoop: no, a male Gardevoir cannot evolve into Gallade. Evolution into Gallade has to happen at the Kirlia stage — specifically, a male Kirlia evolves into Gallade when you use a Dawn Stone on it. Once Kirlia becomes Gardevoir, that path is closed, so you can't go back and turn Gardevoir into Gallade later.
In practice that means if you're aiming for Gallade, keep an eye on your Kirlia and don't let it auto-evolve at level 30 into Gardevoir before you use the Dawn Stone. If you already have a male Gardevoir and feel that sting of regret (I've been there mid-raid), your option is to breed for a male Ralts/Kirlia or catch a wild male Ralts/Kirlia, then use the Dawn Stone on the Kirlia. Also remember gender matters: only male Kirlia can become Gallade, while female Kirlia can only become Gardevoir.
There are some extras that excite me — Gallade gets a Mega Evolution with the Galladite in games that have Megas, and it has a very different playstyle from Gardevoir (more physical attacker, more sword vibes). So if you want that sword-swinging aesthetic and move-pool, it's worth the small breeding detour to get a male Kirlia and that Dawn Stone.