A key member of your team is contentious and is continually questioning the teams decisions

Scenario: A key member of your team is contentious and is continually questioning the teams decisions, even though the team agreed had previously upon its decision-making approach. This particular team member is now consistently missing weekly meetings and his commitment to the team is in question. Respond to the Following Questions: 1.How would you address this individual and handle this situation? 2. If you escalate to the team leader and they do not acknowledge the concerns or conflict that is occurring, how would you respond? 3. If your initial approach to #1 or escalation in #2 do not work and the conflict is still occurring, what is the best way forward to resolve?