I'm not sure. I don't know anything about
your ages, or health history.
I also don't know what the SCD diet is. What is it? I'm interested and would like to know.
You could ready to Brorody article as see what all they test donors for. I know they test for HIV, syphlis, parasites, cancers... but I'm sure there's more stuff.
Of course, I also know first hand how hard it is to ask someone to donate. It not only takes a VERY close relationship, but it is also WAY easier if you live together. My girlfriend is donating for me and we don't live together, and it's jsut not that easy.
Clearly, his intestinal flora is clearly healthier than yours. Probably the best thing you could do is read the article. You can find it at www.cdd.com.au under "publications", or go to it directly at http://www.cdd.com.au/pdf/publications/paper17.pdf
Read up on what they test donors for and talk to your donor at length about his medical history and family medical history to see if he might be "at risk" for something (like a high risk of colon cancer due to a parent or grandparent having had it). If you feel safe... do it. If you're unsure, find a way to get him tested. I remember seeing posts about testing in the history of this topic, but I don't remember where. Or ask folks here about testing and how they got it done.
I certainly understand how difficult some of this is (and how risky) since most doctors don't want to risk their licenses, insurance companies don't cover this, and we (you and me) are not medical experts. I even considered going to Australia to have this done by Borody himself, but I don't have 10,000 to 15,000 dollars, or even credit availability to work with.
keep us posted please! I'm cheering for you!