Do you have a frame on the house, like a Wooden Frame of any sort?
To merely fill holes in the wall...if it's pure brick...than concrete should do fine. The more water you add to the concrete, the more liquidy it will be...but also the weaker it will be, but since it's only holes, you'll want some semi-liquidy concrete. Mix it till it's of a substance that is easily manageable to put into the holes, and stuff it on in. Perhaps another person on the other side can tell when it's squeezing over so you don't put in too much concrete. Then you can smooth it over right there.
Afterwards, smooth it over if it is still rough after it dries. If you make it Too liquidy, you might want to put some boards over the hole or something to make it keep it's form.
On the otherhand, you might want to also add sheetrock and paint, if you have a framework in place already it will be easier. If you have a place to put insulation in the walls, you might not want to do the method I suggested above, instead using a framework and putting up sheetrock, perhaps with some insulation as well. The only way I've done that is with a framework, and attaching the sheetrock to that framework with the wiring and other essentials inside the framework (behind the sheetrock, not actually in the wood and metal).