Minimalism Vs Relationships

It's the way it is being done. Instead of forcing him, perhaps having a conversation and having him make the offer to do something about his stuff. 

Don't force it or have this dealt with harshly because at the end of the day, relationships are more important than having stuff or being a minimalist and we have to weigh out what really matters to us in this life. And if being a minimalist means losing your son, it's not worth it.

And think about fixing that relationship. Remember your priorities. Relationship comes before Lifestyle.