84yrs old male. Diagnosed w/ prostate cancer dr said can't do biopsy or surgery he has 7.50 is this the 3 stage is it why dr don't recommend surgery?

Unclear. I'm uncertain how your doctor knows you have prostate cancer if he was unable to do a prostate biopsy? This is the only reliable way of knowing if prostate cancer is present.
Prostate cancer. An 84 year old with a psa of 7 could have prostate cancer; cannot say without a biopsy . If a person has less than 10 years to live due to health issues psa may not be in that pts best interest; prostate cancer is very common in men aged 80+. A very healthy 80+ year old may benefit from psa testing and treatment but this is a very complex discussion.
Not worth worry. If the value you sent of 7.50 is a psa test result then you can not actually say it is due to prostate cancer. But most people with prostate cancer live >10 years without any treatment. So at age 84, there is no good reason to do any biopsies etc and take the risk of complications!