You are asking if he believes Romans 10:13, I ask if you believe Galatians? Do you think those Judaizers Paul condemned failed to call on the name of the Lord? They merely wanted to add one thing to the gospel of grace—circumcision—and it was enough for Paul to say let them be accursed. He warned about those coming with another gospel.
I understand the impulse to be inclusive, but every one of us is one heartbeat from eternity. Even though it may be upsetting, it is much more loving to tell people the truth while they can find and believe on the real Christ Jesus.
Paul had the council of Jerusalem in Acts 15 verify that the Judaizers weren’t even preaching the gospel in the first place.
So, the gospel is not “circumcision + Jesus”.
The gospel “whoever believes in HIM shall not perish...”
And then God is able to finish the work which He began in you. “being confident of this, that he who began a good work in you will carry it on to completion until the day of Christ Jesus.” Php 1:6