How to provide the Braintree payment option for the multishipping checkout scenario?

The built-in Braintree payment module for Magento 2 does not support the multishipping checkout scenario.

https://github.com/magento/magento2/issues/6467

If you need the multishipping checkout scenario, then use my Stripe payment module, it works very similar to Braintree, and does support multishipping.