Thats a hard one, isn't it? i can understand the yearning for a child that your friend must be feeling and to think that it may not happen for quite some years must be difficult to accept. However, I don't think it would really be right to push a man into being a father. it is such a huge life change that if he really doesn't feel he wants a child, it could end up tearing them apart and if a child was involved then he/she suffers the most.
IMO when the time is right for them both and for the relationship then a child will come along.
For me, when we got married I was 22 and still at uni. I knew i wanted to finish my degree before having a baby, although I did want a child. Now I look back on that time BC (before child) as a very special time for me and DH and a time that we spent preparing and establishing our relationship so it was strong enough to survive a baby thrown in the mix.
Your friend might feel similar in a few years time?