The invading force has to invade. Invade means to enter. You can only enter a place when you are not in it.
There are many better words you can use depending on which side you are. If you are on the side of Hadi, may I suggest the word "coup". That's when a local force overthrows the government.
If a person is on the side of Houthis, they will probably consider their action an extension of the revolution that was started a few years ago.
If a person is on the side of Saleh, they could consider it overthrowing the usurper Hadi.
But in no side, could the Houthis be called invaders. However, the Saudis could be called invaders, as they have forcefully entered a country using force.
It would be nice if you spend some time wasting time on this crap, because you might actually learn how to debate and be able to actually talk like a sensible person, instead of yapping crazily without making any sense.
It's a shame that Yemen is going through such a crisis, but I don't really consider Houthis as my "brothers" in whatever sense you mean. Someone in Yemen doesn't suddenly become my "brother" based on his religious beliefs.