Polly
If he is an artist and he wants to do it he'll do it - and nothing you or anybody else can do will change that.I see my job with DS is to be a facilitator (I certainly haven't an artistic atom in my body) - so I provide the means and encouragement and let him get on with it.

When he took lunch to school he would come back with sculptures made from tin foils and the wax from around the small Edam cheese thingies - just can't help himself.