Dear service user, Thanks for writing to us. I understand the concern. There are several causes of insufficient erections. The common reasons are 1. Diabetes (nerve damage and vessels narrowing) 2. Some medicines like anti depressants and anti psychotics 3. Performance anxiety (the most common reason) 4. Psychiatric disorders (depression, anxiety) 5. Alcohol use (nerve damage and testicular injury) 6. Smoking (vessels narrowing) 7. after some surgical procedures (nerve damage). Let me know whether he can achieve and maintain a good quality of erection in sleep, in the early morning, during masturbation but not at the time of coitus? If he is able to achieve and maintain erection in any one of the above mentioned situations than his problem is more likely psychological rather than physical. Psychological cause is performance anxiety about sex. This can be cured after successful treatment with psychiatrist or sex therapist. Age does not matter in your case. Wish you good health.