There are many people who suffer from inablity of erection of penis during sexual intercourse. It’s called erectile dysfunction - which may be incomplete or complete (Impotence).
There are various causes of it. Some of the common causes are genetic disorder (eg. XXY chromosomes ) , psychiatric disorders, certain drugs ( Beta blockers ) and so on.
This in turn leads to depression and mental disorders. And so it becomes necessary to treat the disorder as early as possible.
There are certain ways to improve erectile dysfunction. Foreplay is one out of them where a couple does some pre-intercourse techniques (play) like touching private parts, kissing, watching movie together etc.
The recommended FDA approved drug treatment for erectile dysfunction is Sildenafil Citrate. It is available in various trade names like Generic Viagra, Kamagra, Lovegra etc. The main difference between Kamagra and Viagra is the price, with Kamagra being a much cheaper alternative.
It is also necessary to consult your nearest Psychiatrist to rule out any psychiatric illness like depression and anxiety ; and to take their regular treatment and follow-up as adviced.
Mutual understanding and co-operation from his wife is always necessary as a supportive psycho-therapy.