Man fertility after brain cancer treatment

I had brain cancer (Germinoma), treated with chemoterapy (etoposide and carboplatin) and brain radiotherapy and the tumor was erradicated.

The oncologist didn't recommend sperm cryopreservation because according to him there was no risk of infertility. Now I have hypogonadism, azoospermia and testicle retraction, and I discovered that it was a big mistake not recommending cryopreservation of sperms.

After that, I consulted with other doctors and now my urologist prescribed Clomiphene Citrate (50mg/day) and said that this is my last chance of being fertile again.

I need help, is this the correct treatment? What are my chances? Are there alternatives?