I am sorry to hear you are worried about Jojo. I am a veterinarian, and will do my best to help. It appears your requested expert is not available so your question was opened to the rest of us.
If you look at his gums, are they pink in color?
Clear mucus from the anus indicates inflammation in the colon, while the vomiting indicates something irritating his stomach. It could be something he ate, or a virus, or a parasite (unlikely if he is an indoor cat).
Is he interested in food
, is he drinking? If he were mine, I might withhold solid food and offer only clear fluids like broth or water for the next 8 to 12 hours. I might try giving him some famotidine (Pepcid AC) 2.5 mg, twice daily for stomach upset/gastritis.
If that slows the vomiting, I would try solid food tomorrow. If he won't eat, or if the Pepcid does not stop the vomiting, I would have him examined by his veterinarian, and consider Cerenia injections for vomiting and metronidazole for the colitis/ colon inflammation.
Glad he is sleeping; good for him to rest. Hope this is just a "24 hour bug" and that he is back to normal soon. Let me know what else I can help with or answer.