I suggest you do two things:

First, buy a copy of a book called, called Saving Your Sex Life: A Guide for Men with Prostate Cancer, by Dr. John Mulhall, which you can find on Amazon.com. Some men and their wives swear by this! It deals with penile rehabilitation post-treatment as well as what else can be done if erectile function is permanently lost.

Second, while you are waiting for the book to arrive, watch this video by Dr. Gerry Chodak that is available on YouTube.

In addition, you can ask your doctors about “sural” nerve grafting, which is mentioned above. However, the results of this technique vary considerably and if you want to have this done you want to make sure it is being done by someone with a lot of experience AND a well-documented success rate in carrying out this procedure. This is a technique that is only offered to the patient at some centers, and only then if it has been decided prior to the radical prostatectomy, that at least one set of the cavernosal nerve bundles has to be removed.

This is a question more than a comment. Thank you