I don't know if Viagra can help after that. If it can't, a penile implant may be needed. But a man should try everything else before that. Or natural remedies, that is. Ginseng is one we are familiar with.
Many western herbs work too.
There's yohimbine, from an African tree bark. The great thing about herbs is that simply taking them often works. It signifies a new attitude of caring on the man's part. Which may be another way of saying love. Zinc is also important, as it is for women.