It would appear from the information that you provided that your father has a papillary tumor (one that looks sort of like a mushroom growing up from the bladder lining,)
It also appears from the word “invasive” that it has grown somewhat into the next layer of the bladder. There is no indication as to whether it has grown into the muscle since apparently no muscle tissue was present in the biopsy sample. Did the report mention whether it was high grade or low grade? Your father, hopefully with you present, needs to clarify with the urologist exactly what the complete biopsy report indicates.
If the cancer has NOT grown into the muscle, and IF it is low grade it is likely that no treatment would be necessary. The usual protocol in such cases is for cyctoscopy every three months for a while to be sure that it hasn’t returned.
Hope this gives you some ideas of questions for the doctor. The primary questions as noted above are whether it is high grade (rapidly dividing and likely to spread) or low grade (slow growing) and if it has grown into the muscle. Age has nothing to do with this.
Wishing you and your father the best...he is lucky to have you on his team
Sara Anne