Please don't let your concern overwhelm you. I think I understand your concern, and it would seem certain that medication improvements keep coming - but try to place your concerns of a possible future negative into a perspective that doesn't interfere with living today. While it is a possibility, it is not a diagnosis.
My Mother is in a well-run assisted living home for Dimentia, and my Grandmother (her mother) was in a horrible Nursing Home (20+ years prior) with Alzheimers. Just the concept of care ... for Dimentia and Alzheimers has changed a great deal in barely one generation. I expect the types of medication have changed as well.
In my personal health issues, I have not worried about becoming a dimentia patient. But ... I am in a battle (10-years so far) with Prostate Cancer, Kidney failure because of the cancer growth (2-years+) and COPD for the past 5-years +. I have tried to find a history of prostate cancer in my family, and I cannot find it!
It could be ... that one generation back people were dying of prostate cancer, but the cause of death was either unknown or mis-diagnosed. It seems to have little history. But, the treatments are constantly changing ... so hope if still alive!!!!
The oral chemo I just started two weeks ago was just passed by the FDA just 11-months ago ... and yet, that treatment now seems to be a pretty common treatment for advanced prostate cancer.
The moral of the story ......... hope ....... whether religious or not, is a key in dealing with so many negatives in life. You and your sons have much time for hope for new procedures, medications and diagnosis. Enjoy your boys and your life today ... and hope for tomorrow.