Romans 14 is the weaker brother/ sister passage. Paul is not implying that because one of us is weak in faith and the other is strong in faith that somehow one is superior to the other. We are not in competition with one another. Paul extends his concept of love to the one newer to faith. That's the weaker brother/sister. And in this case, this person is still learning to settle into walking in the vast freedom we have in Christ to navigate life. It's a lot like school children. They are taught to stay close to the rules as young children. As they mature, there is more freedom to make their own wise decisions. Be loving. Others may not be as comfortable with freedom in Christ as you. Yield to the weaker brother or sister for the sake of Christ.
Todd