I’d love to know exactly what the ingredients going into that were. I’ve heard of the “candy rocket” fuel, which is made by (don’t get any dangerous ideas here kids) mixing potassium nitrate aqueous solution with an aqueous solution of some kind of sugar, in a ratio that has a bit of an excess of sugar. The water is evaporated off to leave a paste (intimate mixture of nitrate and sugar but likely not nitro esters) that can be loaded into narrow paper tube, forming a solid propellant rocket engine. The details of how to do this effectively may be found in a search of “candy rocket”, you’ll find some good examples eventually. One person really(!) did this expertly making a three inch diameter rocket that rose to something like 10,000 ft. DOT will tell you that transporting produced engines is illegal due to being “forbidden to transport” as being likely sugar nitro esters. So, do this at your friend’s home while his parents are at work.