How can money taken fraudulently from a person who was swindled be returned? And must all the money be returned, or only the questioner's share of it? And what should be done if this person dies? And does the prophetic saying "Every body nourished with unlawful earnings, the Fire is more befitting for it" apply to this case?

You and your friend must return all the money you wrongfully consumed. Then, you should recover your friend's share from him. If you are certain the money belongs to your friend's father, return it to him. If he has passed away, return it to his heirs. If all of them have passed away, then give it away as charity with the intention that the reward goes to its rightful owners. Remember that sincere repentance involves restoring rights to their owners. However, if you are unable to fulfill this, repentance is not precluded; rather, it remains a debt upon you that you must pay to the best of your ability. If you cannot, then seek forgiveness from its owners. It suffices for you to have a firm intention to repay it whenever it becomes possible for you, alongside frequent supplication and seeking forgiveness. As for your question about consuming unlawful wealth, the warning in the noble Hadith applies specifically to those who do not repent. As for the one who repents, their repentance erases what came before it.