Well let's be honest, the 159 and Brera are indeed money pits. I dunno what the OP can afford, but if you're starting with a 6k budget I'd rather look into something that is well within that amount and have some left for upgrades/fixes etc.. it would help him familiarise with the "Alfa philosophy" and it wouldn't clean his pockets as much as a 159 would.
But then again if his mind is set on the 159, there's no point in arguing. I suppose the responsible thing to do is warning him that maintenance, tax, insurance and running costs can easily get out of control with a 159, and considering that there are some out there that have loads of big or small issues, it might put him off the Alfa love for good.
I don't mean to be patronising, but IMHO the 159 and Brera are meant for a mature audience (and when I say mature, I mean people that already had an Alfa and know what they're getting on when buying this specific model).
Again, it's just my 2 cents..