Bunkeryest Bunker Build?
http://gw2skills.net/editor/?fUAQNAR7elYgyCXEyKEfIFRugaBYP04H341jEKRGC-j0xAoMioZqRQoQSzJwioxW2KiGr+GTDTEVLFAFjBA-w (Writ of the merciful can be swapped for Superior Aria, haven’t decided)
This is what I use [still missing all the ascended pieces and a few exotic armor pieces ]
High survivability, good damage, but is only at full potential within a zerg. When you first enter WvW kill 25 of the easy npc spawns around (ie moa, stalkers, minotars) with the gs to build 25 stacks of superior sigil of life. Then enjoy! Hope your son enjoys the guardian and gw2, atm my favourite class and game.
I think this is the most tankiest setup you can get;
http://gw2buildcraft.com/calculator/guardian/?3.0|9.1c.h1m.e.1c.hz|2.1c.hz|1c.7r.1c.7r.1c.7r.1c.7r.1c.7r.1c.7r|1c.68.1c.68.1c.68.1c.68.1c.68.8c.68|0.0.u59b.u2ab.a2|0.0|v.1b.18.19.1i|e
But with this setup;
http://gw2buildcraft.com/calculator/guardian/?3.0|9.1c.h1.d.1c.hz|2.1c.hz|1n.7r.1n.7r.1a.7r.1n.7r.1a.7r.1n.7r|1a.68.1a.68.1a.68.1a.68.1a.68.8a.68|0.0.u56b.u2ab.a2|0.0|v.1b.18.19.1i|e
you will have a lot of healing power so every dodge roll will also heal you with 1k and because you will have almost perma vigor with 35% crit chance you can dodge alot, next to this you will have 3 blocks extra because of the 5 skill on focus.
Blunt of Balthazar – 80 Human Guardian
Khan of Feurt – 80 Charr Necromancer