How much to fix a blown head gasket?

[matthew_o50]

My brother was driving home from work this morning after the night shift and his head gasket blew. We haven't seen a mechanic yet because it's a saturday so does anyone have any idea how much this will cost to repair? The car is a 1999 Hyundai Atoz+ 1.0ltr and has done 65k miles. This is the first problem he's ever had with it.

 

[matthew_o50]

My brother's just gotten out of bed after the nightshift and said that he was on the motorway doing about 60 and the guy behind him started to flash his lights so he pulled in to the left lane to take the exit home and all he could see was blue smoke everywhere. There was no change in the engine or any unusual sounds. Also no lights came on on the dashboard. Luckily the exit of the motorway takes you to the bottom of our street so he only had a few hundred yards to go with the car like this. When he stopped he checked the dip stick and it had this yellowish gunk on it. Is this what usually happens when the head gasket blows? Dad thinks that's what happened but he doesn't know too much about the mechanics of cars. If it's not the head gasket what else would cause the blue smoke?