First you will never know what action management took towards this person (unless he is fired which becomes obvious) and you should not. The co-worker's personel record and any negative information in it are not your business. There are many possible actions short of firing the person. Get over the idea that you have a right to know this. Would you want others to know if you messed up and got a waring in your file or got put on an improvement plan? Of course not.
Given you are in a higly audited regulatory environment, you took the correct action and reported the problem. You do have a right to know if there are processes put in place to avoid it being possible for someone to plagerize or to automatically catch it if they do. You do not have a right to know what actions they take towards an individual. You did the correct thing, now the resoution is out of your hands and you need to stop worrying about it.
Given the highly regulated enviroment, I suspect managemnt will take some action, but what I cannot predict. It may or may not qualify as a firing offense depending on many factors including local labor laws, corporate policies, previous performance, reason for the problem, political pressures. The person may be required to be more closely supervised or seek treatment for depression or many other actions. It may be the last straw with this person or the first major problem. The problem may not be a big as you seem to think it is. Local laws are critical here too, it may or may not be possible to fire someone, there are jurisdictions where they need no reason, there are jurisdictions where you have to lots of evidence and show many steps to fix performance and still have difficulty with being fired. Further firing the person can be costly in terms of finding and training a replacement, so it is a last resort generally.
If you do not want to be assigned to work with this person in the future, then you can request that but be aware that means you are likely to end up with the worse assignment out of that not him. You are the one asking for reassignment and will get what is available if there is something. It may not be possible to get reassigned depending on the particular jobs you do. If nothing else is aviable, nothing else is available. Don't expect them to create a new postion for you because you don't like or respect someone. When you do that, then you become a mangement problem as much as the person with a performance issue. You will often have to work with people you don't want to. Such is life. Learn to cope. Protect yourself by checking behind him if needed.
If you like the company and want to continue working there, it might be best to start looking around internally for a project or job you would like to move to where this person will not be there. Requesting a transfer to different position because you want to do it is going to be taken far better than requesting a reassignment because you can't get along with somone.
You can move on to another company as well, but don't do it solely becasue you disagree with the actions management took in this one issue. That is running away because you don't want to learn to work well with people whether you like them or respect them or not. There will be some other problem(s) at another job (maybe even worse ones) and you can't keep just running away everytimne you disagree with management. All jobs after all have problems. If there is a pattern of lots of things you disagree with, then fine move on. Don't let one thing cause you to leave.