Dear Selene,
Welcome to Christian Forums and particularly The Ancient Way. I hope you stick around and become a part of the community here.
It's my understanding that every sexual act must be open to the possibility of conception, otherwise sex becomes a selfish act, gratifying the desires of the flesh. This may seem harsh as I'm certain most people don't think of sex in terms of seeking pleasure for pleasures sake but rather in terms of giving pleasure to their spouse, but deep down I think we can all find selfish motivation. God made us male and female so that we could produce children and he blessed procreation by making it a very pleasurable experience, it isn't the other way around. This is what the church teaches, it is not specifically the teaching of Elder Ephraim.
Having said that, it must be understood that not all are at a point where they are able to accept the above teaching. A spiritual father needs to be able to discern where a person is in their walk with Christ and tailor the medicine and dosage accordingly. As with all medicine, the wrong dosage of the right medicine can cause harm, even death. Unfortunately, some monks (not just those under Elder Ephraim, and not all those under him) are too concerned with the letter of the law and forget the spirit behind it (2 Corinthians 3:6 He has made us competent as ministers of a new covenant?not of the letter but of the Spirit; for the letter kills, but the Spirit gives life.). It is alright for them to be strict with themselves as they are already trained in discipline, but they must be gentle and compassionate with those who are not so trained and come to them for guidance. This is what we find in the lives of the great spiritual fathers. They demanded the utmost obedience of themselves, pushing themselves to ever harsher ascetic labours, yet they never demanded the same of their spiritual children.
Obedience, humility and mortification of the flesh are key to spiritual growth in Orthodoxy. These come easily for those who have grown up in countries where life is a constant struggle either through war or economic hardship, however they are much harder to come by in the West where we have everything given to us in abundance and have so many "rights". It is becoming this way in the East as well. For example, in the monasteries on Mount Athos, most monks sleep on a board and have done so from the day they became monks because they were already used to such hardship. Many of the recent novices and monks, however, have been permitted to sleep on a mattress for the time being because that is what they are used to and would find it too difficult a change to sleep as the other monks do right away. This is how it should have been with your friend.
I should note that in the past my wife and I have used condoms because we did not think circumstances were right for us to have more children then. We regret that now that we are trying to have more children as we have not been able to conceive and we are not getting any younger. We can't complain though. God has blessed these unworthy parents with three wonderful children
God bless,
John.