Start by drawing a vertical line and divide it into 3 sections.
We'll give him a very large forehead to make him look crazy. Draw a horizontal line through the middle of the vertical line. It should be about 2/3's the length of the first line. Divide it into 5 sections, to mark the location of the eyes.
Draw 4 more lines like this to outline the face.
Draw the cheekbones on each side.
Since this is an older character, they stick out quite a bit, and all the facial features will droop a little.
Here, we’ll draw a rather long nose. Note that it should be placed between the 2 central marks.
It should go slightly below this mark in the bottom third of the face.
Draw the eyes on the horizontal line, here.
They should be large and round, but slightly covered by the nose. His left eye is smaller than the right eye.
It's the placement of the eyes and nose that really give him a crazy look.
Adding some shadow here on the forehead will bring out his wrinkles and give him a more sinister aspect.
Continue adding wrinkles around the nose and eyes.
Give him very hollow cheeks by adding lines like this.
Give him big ears that come down very low.
For the hair, it should look very messy, like this.
Draw a ragged mustache and beard as well.
Erase any unnecessary lines.
Add details to the hair...
Draw the eyebrows like this, drooping downwards on each side.
Draw some more wrinkles on the forehead and around the eyes.
Add two small dots for his pupils. Note that they should not be symmetrical.
Now you just need to draw the mouth.
Here, we'll leave the mouth open with only 2 teeth inside.
Add the final details to his beard, hair, and clothes to complete your drawing.