This is just my opinion, but earning 100k when you only have time to spend it between 12am and 7am is a big call. I know a lot of people out of high school don't think of this know, but realistically, is that amount of money (which when you work it out on a per hour basis, isn't that much higher than grad roles where you work 8-9ish hours a day) worth the severely reduced social and romantic life? I do commend your friend appianway for maintaining his relationship as a first year IBanker.
I share the same line of thinking. I've worked at an investment bank before, but in finance and not IB.
I won't divulge specific pay rates because there are some people on here who know where I worked, but the IB grads were getting paid significantly less than every other department (even the back office staff) when you broke it down to an hourly rate.
Hours of work... it's perfectly normal to start at 7am and finish somewhere between 10pm and midnight. It's also considered a normal amount of overtime if you work until 2am or 3am, or start at 5am. Working Saturdays is pretty normal. Sundays is for catching up on all the sleep your missed during the week.
IB has an overwhelming tendency to destroy everything about your life except for your income. And you don't even have a chance to spend your income, because pretty much all you're doing is working, eating and sleeping.
Some people are willing to sacrifice their early- and mid-20s on this sort of lifestyle, in order to financially set themselves up for life. That's a personal and calculated decision, but I implore each of you to realise the full weight of this decision. Family, friends, significant others, sport, hobbies, sleep... they all drop off the radar almost completely. The fact that appianway's friend still has a boyfriend/girlfriend is something extraordinary and admirable. It's definitely not the norm though. Don't be under any delusions or misunderstandings here.
If you've thought long and hard about this and you're sure you're making the right decision for the right reasons, then go for it.