Hello, I would suggest he takes plenty of animal protein diet such as fish and Shellfish rich in Omega-3 fatty acids, etc. Taking Zinc, selenium and vitamin rich food or supplements will be helpful. He should take meat, eggs, green vegetables, fruits such as Avocados, pomegranates, berries, cherries to boost his testosterone levels. He can take supplements to increase his testosterone level. Besides, physical exercise will also help increase his testosterone level to get better erection. Avoid consumption of too much alcohol and fatty diet which have negative effect. Maintain healthy weight and avoid obesity. Sildenafil and Tadalafil are helpful for ED. Consult a GP / urologist for this treatment. Get him examined & required tests and investigations done. In case of any chronic illness that was not diagnosed earlier, get him treated. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician