I can really appreciate your concern for your friend. Although you have said that you need to get your friend back to normal life, you have also said that your friend likes his job and he is a workaholic.
There is a strong possibility of executive stress in your report. This usually can be dealt with slowing down the pace of work and taking regular frequent breaks, engaging in stress relaxation techniques like yoga, relaxation, or enjoyable pastimes.
You need to also appreciate your depth of worry for this friend, which may be excessive and spoiling your own quality of life. It may also be that display of excessive concern may alienate your friend more from you. Also you may in your concern (which may well be very real) treat him/ her, as a child in a paternalistic way, which may make matters worse.
I suggest that to be able to do justice you should be able to approach your friend in a more realistic way, give him adequate space and understand and do as any mature individual would do for another individual.