I think the best way you can go about keeping a question open is to review it in the close queue. Currently at 4k+ rep, you have enough rep that grants you access to that queue and the privilege to cast close/keep open/reopen votes on questions.
Reviewing close and reopen votes
Any post which currently has an active close vote or a close flag will appear in the Close Votes review queue. In this queue, users can either vote to close the question, edit the question, or recommend leaving it open. Edits or a sufficient number of "Leave Open" reviews will remove the question from review and immediately begin aging the close votes. If the question receives another close vote after being kicked out, it will re-enter the queue for further review. Questions with vote to close as a duplicate will also list each possible duplicate in a tab at the top for easy reviewing.
The "a sufficient number" part sounds vague, but I am led to believe currently the number is 3. That is, if three people have reviewed that question and voted to leave it open, it will be removed from the close queue. But it could still be closed when others see that question and cast enough close votes.
Alternatively, you can vote to reopen it once it gets closed.