Twenty days is very early in sobriety. I know in my very first days sober I had to put sobriety Front and Center. Sobriety is still my first priority and always will be, but at four months I'm feeling comfortable in other areas of my life.
He could be taking the Big Book's advice totally literally about not having/forming relationships in the first year of sobriety. Altho I don't know if the BB means to ignore a relationship you're already part of... I kind of doubt that, but it depends on HIS interpretation of the "no big changes/relationships in the first year".
Do you go to Al-Anon meetings? Might be a good way to get a handle on why he's doing what he's doing - but the best way is to ask him, nicely, of course, and non-threateningly. I commend him on getting sober, but the very early days of sobriety is a rough ride, so you may have to step back for a while as he 'gets his bearings'.
All the best to you!:ghug3