Depression is a life sentence of just trying to stay functional for many many people. Look at Robin Williams for a high profile example. You never get "well" from it.
While that is saddly true for many people, it is not the norm.
And yes, it's different from a broken arm, u will likely not be the same person afterwards, most likely the view u have on many things has changed, people and society especialy.
I had to suffer that shit for 10 years myself, but it got better after a lot of work, therapy, medication and a lot of setbacks. And yes i would say i'm well again, same for others i know. I wouldn't say, i'm healed thought, as the disease accompanies u to a degree. U learn to live with it and how to cope with bad days, but u can have a happy life again.
People are rarely, if ever, fixed from depression, it's easy to slip back.
Depression is shit, but it's not that it can't be treated, in many cases the chances are even good.
For major cases it's often a long and tedious path, which most of the times leaves some scars. The chances are still good in general, but yeah life will be different after that, still many live a happy life after a successful treatment.
The risk of falling back is always there that is true, but that's what therapie is there for, to teach u how to identify early signs and how to counter them, also to find a individual way to cope with it if it hit's again.
Also the most depressive people are not in a bad spot every day (that's mostly the case if u are in a acute phase), they also have good days, weeks or even months in beetwen. Depends what sort of depression of course.
In many cases the larger problem after a succseful treatment is society...there is a stigma on pretty much all mental diseases, lack of understanding, prejudice, often hard to get a job ''a lack of endurance, or too risky, even dangerous''...etc. It's hard to start new after a depression, because the old life will often not an option anymore.
But the MC hitting and falling for basically every girl he sees, going horny teenage boy and then whining he brings them in danger has not much to do with that.
As for the end,
well he didn't try to save the girl...how about ''Ubel save the girl'' it may have failed, but at least he would have tried.
But good, i can understand he feels shitty for not saving her, but being a monster for killing the murderes which find the whole thing amusing ?...not to mention 2 sentences later he is fawning how beautiful the butterfly-girl is 
...
Overal i just think the MC needs to make some progress, the depression part was a good start, good written also.
But the most he does is hitting on girls, sleeping with them and then feeling bad for it, before he meets a new girls and is hitting on them...i mean, take ur pick.
Either feel shitty for using the girls and involving them in this mess. Try to make them feel as good as possible, but then stop going horny teenage boy on every damn girl u meet and stop adding more to the list.
Or enjoy all the girls are throwing themself on u and take full advantage of that glamour, but then stop the whining.
Using the depression as an explanation here, just doesn't cut it. Neither does it make u a horny teenager nor does it make u retarted so that u repead the same 'mistake' time and time again.
