All perfect praise be to Allah, The Lord of the Worlds, and peace and blessing be upon the Messenger of Allah, his family, and all his Companions.
It is incumbent on your friend to repent to Allah, The Exalted, of kissing a woman who is unlawful for him and going to that party where he drank alcohol. You should also advise him and remind him of the need to repent; Islam is founded on the exchange of sincere advice, as the Prophet, sallallahu ‘alayhi wa sallam, said. If he rejects your advice, there is no good in keeping the company of a dissolute person. The Prophet, sallallahu ‘alayhi wa sallam, said: “Do not accompany except a believer, and do not serve your food except to a pious person.”
However, the relevant warning for those who drink Khamr (intoxicants), having their prayers rejected and what you have mentioned in the question, do not apply to him because merely tasting something is not called drinking. Therefore, when a fasting person tastes food and it does not reach his throat, it does not invalidate the fast.
Allah knows best.