These issues may not be solved only by a lifestyle. Trouble sleeping and overwhelming stress may just be symptoms to a bigger problem such as depression. A good friend would suggest to speak to a medical professional. If your friend wants to sleep better they need to have a night routine, turn off all electronics and lights, not eat or drink too late, and just clear their mind. If they are stressed they need to learn to meditate and release stress healthily such as through exercise (sports, gym, running) or by writing down in a journal or just talking to a good friend such as yourself. If these things don't help then it is important to see a doctor and find out if there are any other serious problems that can't be solved by lifestyle change alone. Good luck!