Hi Ben. The twelth house is traditionally the house of self-undoing as well as hidden enemies.
But anyway, I think that anything in a chart is a potential enemy to the extent that it hasn't been made conscious. And of course when planets are linked by hard aspects it is more likely that one of the planets will be relegated to the unconscious to some extent.
I would tend to read the Mercury Venus Mars configuration as a midpoint configuration which is especially potent because aspects are involved as well. In other words, I would see it as Venus semisquare Mars, with Mercury=Venus/Mars. Though obviously right to say that there is an 8th harmonic thing going on here because in the 8th harmonic Mercury would show as being opposite a Venus Mars conjunction. You could call it a 16th harmonic syndrome, since the three planets' 16th harmonic waves are in phase.
And then there is the Sun Jupiter Neptune 8H syndrome too, with Mars square Neptune and Uranus and exactly square the Uranus/Neptune midpoint.
The chart suggests a bias towards the air and earth in the way your son adapts to life. It strikes me that different parts of the chart will seek truth on different levels and for different reasons. The Sun Venus rising in Virgo will seek practical understanding which enables him to maintain order both within and around him, and this will facilitate the strong need for creative endeavour shown in this part of the chart. The Libra part of him will seek a more intellectual understanding which helps him to maintain harmony in his dealings with others. The mutual reception between Mercury and Venus in this chart underlines the traits which these signs have in common - both Virgo and Libra value co-operation and are both inclined to give way to others rather than engage in conflict and discord.
In terms of your question, I think that perhaps the Sun Jupiter Neptune configuration can in some cases lead to a kind of identification with a spiritual vision of life. It may be difficult for your son to see the truths that he perceives as something separate from who he is. It is important I feel for him to develop a strong ego so that he can express such visions as an individual rather than be taken over by them.
Mercury aspecting Chiron and Uranus could reflect an intellectual loner, whose ideas somehow set him apart from others. This could add to the angular Pluto and Moon in Scorpio tendency to feel alienated. The sextiles from the Moon to the Ascendant, Sun and Venus could offer this intense and passionate Moon a channel for the Moon, which may add an emotional intensity to the way he expresses himself to others. Scorpio and Pluto of course reflect a profound need to seek truth and can feel it to be a matter of survival to uncover that which is hidden from them.
Saturn is weakly aspected in the 7th, suggesting that it may be projected onto others. It is sextile Neptune and in Pisces, so here again is the need to ground a vision according to his own integrity. Saturn is also opposite Chiron, and this could add to a sense of intellectual alienation - he could feel that he is up against the established values of the collective in his attempts to discover and express understanding.
One last thought - his IC, often associated with the experience of being fathered, is conjunct both Jupiter and Pluto, and is on the Jupiter/Pluto midpoint (if birth time is accurate enough). So it interested me that your post concerned the realisation of his Pluto potential (Jupiter being to do with openness to new possibilities of expression).
I wouldn't approach this in terms of controlling the minor aspects. My guess is that he just needs more time to consolidate a sense of self (as is often the case in young people with strong outer planets). The crucial thing is perhaps that he values himself, and his individual needs, as an individual so that he has a solid ego from which to operate. Without this strong ego, Sun Jupiter Neptune can develop into inflation, with any unhealed wounds (such as might be reflected by Mercury-Chiron, Moon-Scorpio & Pluto IC, Saturn, Mars-Neptune) expressing covertly and compulsively.
witch affects romantic area. 