double up on craft wondrous. with the possible exception of craft arms/armor (which he got as a bonus feat if i remember the archetype correctly) in a martial heavy party, wondrous items will be by far the most often wanted magic items in the party- having 2 people who can craft them (and one who may just do that and not come on adventures) will greatly reduce the amount of down time between sessions while players are just waiting for their new goodies to be crafted.
My brother plays a Forgemaster Cleric as a cohort.
We've found that the Reach Spell metamagic feat is a really, really powerful choice for the archetype because of the archetype's divine smith ability. Essentially, if you modify a spell that targets a weapon with a metamagic feat, you reduce the feat's total spell increase by 1 level. Combined with Reach Spell, you can boost all of the weapon-and-armor targeting spells in the game that usually require the caster to touch the object to close range (25 ft. + 5ft./2 levels) with no spell level increase. Its been helpful to have the cohort cast spells like weapon of awe from halfway across the battlefield.
alexander's suggestion is interesting and raises an important question: is this going to be primarily an adventuring cohort or a crafting resource?
if the latter, add craft wondrous and find a safe spot where he can work fulltime crafting while you adventure. if the prior, give him reach spell or extend spell since he'll mostly be supporting the party through buffs and heals/status-removal (and remember that he can get 2 hours of arms/armor crafting done each adventuring day).
Scribe scroll if he doesn't have it already. Maybe get him armor and weapon crafting feats as well as that other fancy stuff?
Inscribe Rune is a good one too. Having someone on hand who can put a Rune of Resistance on everyone in the party can definitely make this dwarf worth his weight in gold. If that's not thematically appropriate for this guy though, then yeah, Reach spell is a great one for a support caster.