im training my mom's friends son but i really don't know where to start because he wants to lose weight while gaining muscle and we are training together 5 times a week but im only trying to build muscle so would it be possible to make a program so i can reach my goal while still helping him reach his? :-)

Let me put it this way. It is theoretically possible to lose fat and gain muscle at the same time. However if you do not know how, you do not know how, simple as that. That type of knowledge is insanely hard to reach as it requires in depth information about macros, micros and training. Best adivce: Focus on one thing at a time. Lose weight: Do more cardio and eat less. Gain muscle: Lift weights and eat more.