He will not know for sure until the foreskin is loosened somewhat more.
If he can get the foreskin to retract whilst erect, I am sure that a steroid like betamethasone valerate will help.
Even after I first experience vaginal penetration, my foreskin would not retract even when flaccid. Even a slight tug would cause discomfort as only a small opening existed. Whilst I use condoms anyhow, it was the only thing from allowing me to penetrate without the risk of damage to the tissue at the time.
Whilst I used the steroid that I have mentioned, betnovate in the uk, stretching was easy up until the point when I realised that I had a short frenulum. Fortunately, even this stretched just enough for me to achieve complete comfort in penetration. Couple that with the fact that it is of the thick variety, and it is strong enough not to tear.
Sometimes it will stretch, other times it requires an operation which will hopefully leave the frenulum intact, whilst effectively adding length to it.
The only problem that I have now is that if I do not keep up the stretching techniques that I have used to great effect, the skin will tighten.
I would rather deal with this, than having the extreme circumcision performed upon my person however.
Do not make any rash decisions, and use all tools at your disposal.
Aside from steroid ointments/creams (which ever you prefer), warmth should aid you in your manipulation of the skin. Even seamen itself may (though do not quote me on this) contain qualities that aid with stretching.
There is absolutely no need to rush this.
It can take weeks (which was true of me despite having only a small opening available) to around 6 months.
When the time is right you will be using protection any how I trust (unless you are the type who believes in marriage before sex, which is up to you). This will help you work out what feels comfortable and what does not.
If the worst comes to the worst there are partial circumcisions (although some surgeons will refuse to perform them or even claim that there is "no such thing").
Even when circumcised one can retain some of what is lost (but not all) through foreskin restoration techniques. I have not looked too much into these, but I am quite certain that they do work by actually promoting skin growth, as opposed to mere stretching.
Good luck, and think positive.
Be prepared to encounter doctors who tell you such and such is not possible. This is something that is not understood well in the uk and us a like. Not sure about other countries.
It does seem however that the medical profession are getting to grips with the other options available.
