Just go out and have fun. Do something so fun he forgets, even if it's a moment. And he'll appreciate it. The only thing that will get him off things is time.
Do some sports or any activities you both enjoy. Try to avoid things and places that reminds him of ex. If need an outlet of frustration, boxing on a punching bag. If necessary, ask your other friends for help, eat at the mall, karaoke night, etc. Surround him with friends and support. Let him know that he has friends to rely on in time like this. Friends stick together.
You could help him accepting himself through learning his shortcoming that caused the breakup, once he learn to accept the break up he may be able to move on quicker. Or help him get back to the single lifestyle, make him realize breakups are normal and he shouldn't lose himself to a relationship. Now is the chance to discover himself, let him grow from this break up. In my opinion , you are doing well in helping your friend's breakup, you don't need to do anything special, as long as you continue to sincerely support him and guide him from making regretful choices it will be enough.
1. Teach him Da Wey of escapism via games, novels, whatever. 2. Wait for him to lose most, if not all, qualifications of being a productive member of society. 3. Introduce him to 2D girls who never leave him. 4. Profit (for entertainment industry).