If he wants a good regiment look at 29 Commando Regiment RA or look at 7 RHA who have the Parachute support role.
Light gun is not being phased out, but there are a lot of changes in 2012 that will affect the regiment such as 40 Field Regiment (The Lowland Gunners) which is currently light gun roled, being disbanded, with 137 (Java) Battery being put under 19 Field Regiment (The Highland Gunners) and then being called the Scottish Artillery Regiment (at the moment but this may change)
A lot of Royal Artillery Regiments are now roled as Drone regiments flying the drones which range from small hand held to large drones.
If he is interested i joining the Royal Regiment of Artillery, contact Larkhill and speak to them down at the Royal School of Artillery.
If he wants a good life but hard working look at 29 Commando Regiment Royal Artillery.