For about $300/mo you can have a personal assistant who will do what he wants to have done with phone calls. But, for free, you can have Google Voice, which yo

For about $300/mo you can have a personal assistant who will do what he wants to have done with phone calls. But, for free, you can have Google Voice, which you should get anyway if you travel internationally or use Hangouts, which will block spam calls and screen calls from numbers not in your known contacts. If he works with a group of people in a consultancy, there are numerous small business pbx-aaS services that have auto-attendant features for call screening or that can be used in combination with a human personal assistant.