Possible Clues:

• As tonic, take tablet if laid up
• 19, which sounds like a boy's name
• Charge one penny for boost
• Encouragement, stimulus
• The boost he might give one, by the sound of it
• Boost for Alexander's father, say
• Stimulus (sounds like a boy!)
• Something adding stimulation
• Write up tablet if needing stimulus
• Sounds like the boy needs medicine if he's backward