This is fucking retarded, but to add to your plot Ben should show all his friends the forest and they corrupt it and destroy it and smoke almost everything and Sensi's almost dying until Ben saves the day by slitting all his friends throats and cutting them open and burying their guts into the ground as fertilizer for the soil and then he cuts up Sensi and plants parts of him to grow more plants and keeps the forest alive and because of the dead bodies as fertilizer it causes a reaction where Ben starts turning into the weed creature.
Honestly how the fuck could you say this is for a children's book?