Dark Matter and Black Hole!!

A few days back, I was having an interesting discussion with one of my friend in a public forum known as Actaphysica http://www.actaphysica.com/ . He seemed to be an expert in Black Hole physics who opened various threads related to some interesting aspects related to black holes, hawking radiation(HR) as well as dark matter. He talked about the possibility of a black hole formed out of two unstable micro black holes. As we know the black body temperature associated with a black hole in inversely proportional to the mass squared. Thus smaller the mass is , higher is the temperature and sooner the black hole will evaporate. I had a doubt while discussing the possibility of an atom formed out of a black hole with charge -1 and mass $m_e$ which we call and eBH (electron black hole) and another with charge +1 and mass $m_p$ which we call a pBH (proton black hole). I raised the doubt saying that eBH being tiny will evaporate soon by emitting HR and hence there won't be any bound state forming between eBH and pBH. But my friend pointed out that only isolated black holes can radiate HR and finally evaporate. Thus within a bound state eBH and pBH won't be emitting HR. However if the radius of their bound state is smaller than the corresponding Schwarzchild Radius then the bound state itself can behave like a black hole and hence emit HR since the bound state is an isolated state by itself. This would be , according to him, a ground breaking result since so far people have no idea about internal substructure of black holes. One more interesting aspect of such bound state could be the relation with dark matter. If the bound state does not become a black hole then it would be a stable entity and hence can be studied from dark matter point of view. I do not know how much work is done in this direction but it seems like an interesting field to explore.