There is pen & ink and there is charcoal art work.
Sometimes he asks me if he should stick to one medium but my answer is to go with the flow, I could never be bound by one type of medium and he does lovely work in every kind.
Here are a few art pieces here for Black & White Friday for you to see.
The thumbnail is a figure study in black and white, and in this shows the lighting. When a person draws or even take photos it pays to notice where the light is coming from, and there is a clue to good photography and art work of any kind.