I'm sorry to hear about your boyfriend's diagnosis - it is a shock and will affect people differently.  Personally, I was a basketcase for about 3 weeks after my 16 year-old son was diagnosed with metastic Ewings in January 2015.  I'm US by the way, so some things may be different.  

It's natural to be scared - Ewings is a no-nonsense type of cancer with an aggressive treatment plan.  Perhaps your fear is not of the chemo itself but the "what-if's".  What if things don't work like they are supposed to, what if the doctors were wrong, what if... [I'm not going to go into my own fears because I don't want to give you any ideas!].  You may hear two things over and over again that sound like empty platitudes but can be helpful.  The first is "Take it day by day" - that's about the extent of our control over this situation.  You will worry about the future, but there are so many uncontrollable events that you shouldn't spend too much time worrying about them.  Worry about what you can influence today.  How is he feeling today, what can I do for him today, what I can do for myself today so I can be ready for tomorrow?  Do not forget yourself - he's got lots of doctors and nurses and other caregivers, you do not.

The second thing you may hear is "It's a marathon, not a sprint".  The treatment is long, as you know.  There may be times that he is tired from being poked & prodded all night, or weak from not being able to keep food down, or just worn down from the cumulative stress.  The Ewing's patients I know about are some of the strongest people I've ever known.  While the doctors are doing their physical thing, don't forget the mental / emotional thing - the hospital may have therapy resources for him as well as family & friends.

At the end of treatment, he'll hopefully be diagnosed as NED - No Evidence of Disease - meaning there's no noticeable indication of Ewing's.  A common definition of cancer free is being NED for five years after completion of treatment.  Depending on where his tumor is and the extent of treatment, "fine" could mean lots of things - the key is that he is NED.  Everything else can be dealt with.

My son spent lots of time in the hospital - the US treatment protocol calls for 14 rounds of chemo (3-4 days in hospital, off a week, 5 days in, off a week, 3-4 days in, etc.), as well as surgery if necessary and radiation (generally outpatient).  That's a LOT of time there.  Check for wi-fi availability in the hospital - ebooks, physical books, some computer games worked well (most did not), movies and TV on disc or downloaded, schoolwork also (if he's still in school?).

My best to you, to him and his family.