Only the 144,000 anointed have the Spirit; the 'other sheep' do not.
The JW two-class system creates an impossible situation: the vast majority of JWs, by their own theology, do not have the Spirit dwelling in them, yet the Bible says you cannot please God without the Spirit.
By the Watchtower's own theology, most JWs cannot please God.
Various attempts to distinguish types of Spirit activity.
Paul's language is absolute: 'If anyone does not have the Spirit of Christ, they do not belong to Christ.' There is no third category.
Do not lecture. Ask the question and let the silence work.
Read the first half of Romans 8 slowly until you can walk through from memory, especially Paul's line that anyone who does not have the Spirit of Christ does not belong to Christ. Check how the NWT words those two verses, so you can point to their own Bible. Practise the doorstep question aloud and then stopping; letting the silence do its work is harder than it sounds and needs rehearsal. Expect an attempt to distinguish different kinds of Spirit activity. Prepare one calm reply, that Paul offers no third category, and resist turning it into a lecture.