Bocabuster makes very good points.
Although, I would add that it is possible for a sudden increase in BP due to other issues, the aging process not withstanding. I am sure his doc has gone over all possible causes to eliminate any root problems that need more urgent addressing.
Viagra and Cialis both work to dilate blood vessels to increase blood flow to the penis. This means that it also dilates blood vessels everywhere else and in combination with your BP meds, can cause an unexpected and serious drop in BP causing you to pass out (or worse because the Viagra/Cialis stays in circulation in your blood stream for more than an hour).
Sex will lower blood pressure so have it and keep up with it, just avoid trying to imitate porn movies. Not only is it bad for your heart, it is usually pretty damn boring to the point of being irritating to your female partner. LOL
The only thing I would say about BP meds and being over 60 as important (in my mind) are these things:
1) Stay well hydrated all the time and don't wait until you are thirsty. Your thirst signals will not work as well as you age and most BP meds act like water pills and can cause a really mild dehydration.
2) Not only will dehydration make medical issues worse, it will also turn your ejaculate into the equivalent of thin horse glue. Ugh!
3) Stay compliant with your meds and listen to your doc. Always tell your doc about anything new that happens in your body, even if you don't see how it is connected.
Be well