I totally understand - I had dental phobia for years, and even now i have to really force myself to brush my teeth, and if I see someone doing it on TV or in a film, i have to look away and block my ears.
The fact is, your friend is only prolonging the inevitable, with the side issue that the klonger he leaves it, the worse it will be when he is forced to go, and the pain will do that if he waits long enough.
A lot of dentists will supply medication for nervious patients, if the local one won't, ask him to speak to his doctor who may be able to help.
The fact is, ignoring this issue is not going to solve it - he has to be mature enough to accept that, and do something before he gets into serious long-term health issues.