home made cough sweets didn't set properly

you need a Candy thermometer. Sugar needs to be heated to the soft or hard crack temps in order to set as desired. If the sugar does reach the needed temp, then it won't do what you wanted. Hard crack makes hard candies, soft crack makes softer but firm candies.

Your Sugar was having water content more than desired & hence it could have been runny.

My Cough Candy Recipe

• 1 Cup Sugar
• 1/2 Cup Water
• 1 Table Spoon Honey
• 1 Table Spoon Lemon Juice
• 1 Tea Spoon Dry Ginger Powder
• 1 Tea Spoon Licorice Powder
• 1/2 Tea Spoon Clove Powder

Methodology:

• Mix all Ingredients in a Open Mouth Vessel
• When all contents are mixed well, heat the Mixture over Low Flame
• After 10 Minutes, increase the Flame by Half
• After 10 Minutes take Vessel of the Flame and allow it to cool at Room Temperature
• Drop the Mixture over Baking Tray or Non Stick Greased Surface, with Spoon, making small Lozenges
• Allow to cool fully & dust with powdered sugar

In India Sugar Syrup, also known as Chaasni, form a core ingredient in many Desserts. Indians have their own traditional analysis method when cooking Sugar Syrup. A drop of cooked syrup is kept on tip of Index finger, its slightly pressed by thumb tip. On slowly raising the thumb, thin threads of syrup can be seen. The number of threads help identify consistency & usage of Syrup. In case of Candy making, 5 threads syrups are the best. I know it would be very primitive to use such methods, but really certain things rely on Intuitions & Proximity.