Prostate Cancer & Malignant Melanoma: Should we get a 2nd opinion?

My father was diagnosed with Prostate Cancer in March of 2021 with surgery to remove his prostate. His PSA in May, after 6 weeks of healing, was .125. One month later in June it was .25 and in July it was .50. So, the surgery did not get all the cancer out. It was then in his lymph nodes. He began hormone therapy with for 2 months prior to 37 rounds of radiation. From just receiving the hormone therapy his PSA went from .50 to .08 prior to the radiation. So on December 2nd he graduated after completing 37 rounds of radiation in 2 months. The hormone therapy will continue for a total of 2 years (every 3 months injection), per recommendation of dr.

We all thought he was out of the woods, but God had other plans for him. He developed what we thought was a cold score on his lower lip during the radiation. On November 23rd he went to the dentist, and she said this was not a cold score, but thought it was some kind of cyst. So, we made an appointment with ENT to look at it. She tried to remove all of it but was unable to. It was sent for biopsy on January 4th, 2022. Well, low and behold it came back as Melanoma! So, we begin again on the journey to get rid of this cancer.
Had a CAT scan January 18th per dr Head and Neck Surgery, Otolaryngology
No lymphatic or tissue abnormalities! No metastatic involvement! Great News!

NOW HERE IS WHERE WE WANT TO MAKE THE ABSOLUTE BEST CALL FOR SURGERY AND RECONSTRUCTION AND IM HAVING A HARD TIME WITH IT.
We saw Dr Jennifer Bruening, Otolaryngologist

She is new to Froedert Hospital, and this would be her FIRST reconstruction of the lip.
She completed her undergraduate degree and medical school at the University of Minnesota- Twin Cities, double majoring in Biology and Physiology at the College of Biological Sciences. She then went to the University of Pittsburgh Medical Center for her Otolaryngology-Head and Neck Surgery residency in the research track, where she spent an additional year in Robert Ferris's lab studying the impact of the immune system on HPV-associated cancers. After residency, Dr. Bruening completed a fellowship in Advanced Head and Neck Surgical Oncology at Oregon Health and Science University in Portland, OR. She then stayed to complete a Head and Neck Facial Plastic and Reconstructive Surgery fellowship, focusing on microvascular reconstruction under Dr. Mark Wax.

Today she said the surgery to remove the cancer is easy, but she has to take wide margins because she doesn’t want to have to come back and repeat it. She has to remove half of his bottom lip.
The tuff part is reconstructing it. That will take about 2 hours. They use his lip, cheek, inside, mouth, outer cheek tissue to reconstruct that lip and last resort would be a graph from leg.
She will also take a few sentinel nodes out and have biopsies done. Hopefully he won’t have to have the Parotid gland involved.
My dad will have a 1-2 month recovery time. He may need to learn how to talk, eat, swallow etc after this procedure. He will have a feeding tube for at least a week.

I know this is a very lengthy post my apologies for that. I just want to make sure you have the whole picture. My main questions are because my father is 71 he is only giving this one go at it and I want to make sure we are making the right choice. Should I be getting a second opinion? Should I be taking him to MAYO? When I look up oral malignant melanoma it says "silent killer"
Is it just me or does this dr have studies in multiple areas and reconstruction is not her primary?
Does the immune therapy have anything to do with this cancer? With the timing its something that's on my mind.
Should we be having a PET scan also?
If anyone has any experience with this, I would really appreciate feedback and FAST!
Thank you for your time!