I had the HD Brachytherapy, not the seeds, which meant there was a high dose of radiation directly into the prostate for a short length of time and then the source was removed. I then followed up with 15 treatments of external beam radiotherapy to the prostate and pelvic area.
I was fairly side effect free directly after the treatment apart from tiredness. However after about 6 weeks I found that I was having problems going for a pee. I didn't actually have retention but had the urgency to go and found I couldn't or could only pee a little. It was also very stingy and unpleasant. I spoke to the specialist nurse at the hospital and also the Radiotherapy team. They advised me to increase the Tamsulosin I was taking to help improve the problem. I started taking one tablet in the morning and one in the evening which helped. After 2 weeks I was reasonably OK.
I am back to just one tamsulosin in the mornings now and my peeing is fairly ok. I still get a little burning occasionally but it is easily tolerable.
I have had some ED but that seems to be improving now and fortunately I've not had any other problems.
I am happy I took this course of treatment and hope that your friend has a very positive outcome.