Dear Margaret, 

If your nephew is truly convinced that he is called to marry, then he should make sure that he goes about it in a similar way to a young man who thinks he is called to the priesthood. Surprised? 

What I mean is, prayer will only get you so far. Prayer without our cooperation will not bear its full fruit.  

Prayer purifies our will, makes us capable of knowing what we are supposed to do, strengthens our spirit to follow Christ rather than the world, stirs up love for God in our soul, etc... That is all hugely important, but nevertheless incomplete. So your nephew has to complete his side of the equation by developing a normal, healthy (in a Christian sense) social life for a single man of his age. Social life is not limited to dances and parties. It is involvement with others. Teaching CCD in the parish can be part of a normal social life. Participating in choir, helping in youth groups, volunteering to coach in the parochial school or in the township, drama clubs, sports clubs, service projects... Any of these and many more can be the way God wants to answer his prayer and have him meet that 'special person' he knows must be out there.