All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
A Muslim believes that this world is only a short phase that will surely end very soon. The success and failure of the eternal life depends on the deeds of this short life. So, one has to always prefer the immortal life on the mortal life. All the Islamic teachings are based on the benefit of human beings in this life and Hereafter as well. Whenever one violates those teachings, indeed he/she will suffer in both lives.
Living in a non-Muslim country, travelling without being accompanied by an unmarriageable man, mixing with alien men or being alone with them, all are major sins. Satan incites people on doing small sins, gradually he pushes them to the horrible sins and then it becomes hard for them to return back to the right path.
For more details on the mentioned issues, please read Fataawa: 85589, 83795 and 84281.
Now, every one who has committed a sin should sincerely repent before he/she face the agony of death. So, your friend has to repent sincerely from this sin immediately. Giving up the sin for the sake of the religion is the core of the sincere repentance. To know how to make repentance refer to the Fatwa: 81467.
Fasting sixty days becomes due only if one had practically engaged in intercourse during the day of Ramadan otherwise one only has to make up all the days in which he/she has ejaculated the pre-seminal fluid or sperm.
Allaah knows best.