Your friend is doing the best thing right now and that is seeing his physician. He is very lucky to have you and you obviously care for him. I believe contacting his family may be the best way to help him and perhaps his family could do an intervention and arrange to have him hospitalized to keep him safe while he iis under the care of a physician.
I do not think that keeping his secret is a help to him as he is not thinking straight so enlisting help to provide care for him would, IMHO, be the best way to support him.
Remember you cannot change another person, and you are not a professional but a good friend so help him get professional help.
I have posted the numbers above for the Crisis Hotlines.