What planatery configurations are causing his pain?,
First thing that struck me was natal Neptune tightly conjunct IC/home roots. This suggests sacrifices, illusions concerning family members and secrets kept from them, skeletons in the closet. Maybe he is still dealing with these demons from the past/childhood now?
Although T Saturn is trining Moon conj MC, it's also Quincunx natal sun in 6th house of health and as T Neptune is also conjunct sun it's also quincunx T Neptune. I feel THIS is the trigger - a fear of the unknown. apprehension about health, state of mind. Aquarius sun is quincunx sign to Virgo the natural ruler of 6th and these two signs don't have a lot in common. Now quincunx are bit like an itch you cant' scratch and do cause health strains unfortunately.
His Virgo Asc is also at odds with his core beliefs, ego and pride. The way he presents himself to others -- is not what's going on underneath, that's sun. This sun is also a singleton
A person with a Sun singleton may appearquite Uranian. But where Uranus intends to be bizarre, the Sun intends to show his specialness and uniqueness. The effect is similar, but the motivation is different. The Sun and the sign Leo are fundamentally “conformist” while Uranus and Aquarius are basically “radicals” and “revolutionaries,” “bohemians” and societal “deviants” or “rebels.”
This brings us to the Sun singleton’s greatest tendency and worst fear: to fall into the qualities of it’s opposite. For example, a Sun singleton in Cancer may become an absolute dictator, or fall into the Capricornian archetype, while a Capricorn singleton Sun may become the eternal baby, the Cancerian archetype. With all singletons
extremes of expression,
or extremes of repression, are to be suspected.
http://www.astrologyclub.org/
Does he display any Leo bossiness, wanting to be centre of attention?
Another internal lifelong struggle is sun square moon
"Self-expression is blocked by emotional hangups or habit patterns that may be inherited or conditioned by past events. Family and domestic affairs keep you from developing the way you would like.
The conditions in your early family environment may have caused difficulties in understanding and getting along with the opposite sex. In these relationships you can be too argumentative and defensive. You may need to get the chip off your shoulder sometimes. This aspect suggests a conflict between the ego and the emotions.
There is a presence of tension between your outer and inner self"
http://www.skyscript.co.uk/sunaspects.html#susmo
A helping hand would have been mars which is trine to sun, BUT it's Apex for Yod configuration
Waybread is right, this is a difficult chart BUT I do see a mystic rectangle in there for assistance and this is where the focus should be on these planets there aspects and how they integrate in the personality.
Although Neptune is challenged it does have 4 trines to help other energies flow for assistance
Mystic Rectangle also know as Grand Rectangle
http://www.astro.com/mtp/mtpt82_e.htm
http://www.lunarliving.org/astrology/mysticrectangle_wedge.shtml
http://www.skyscript.co.uk/aspects2.html
http://www.therealastrology.com/HTML/FAQS/AspectPatterns.html#Mystic Rectangle
http://www.aquamoonlight.co.uk/aspect-patterns2.html
Hope he gets better soon, best wishes