To stop division, stop dividing
Provided our brother hasn't departed from the gospel, is not engaged in immoral conduct or character, and is not being divisive (advocating division), there is no reason that brotherly love can't overcome all other scruples.
- 1 Corinthians 12:24-25 - But God has combined the members of the body and has given greater honor to the parts that lacked it, so that there should be no division in the body, but that its parts should have equal concern for each other. (NIV)
But above all, let's not divide the people of God or reject any one of them over his "error arising from weakness of mind":
- Romans 15:1 - We then who are strong ought to bear with the scruples of the weak, and not to please ourselves.