That is certainly not possible. At least not through our service.
We provide our own phone numbers through our service, and you can only use a number from another carrier on our service if you port in that number to a wireless account with us.
If they had ported your husband's phone number to their account, then your husband would have lost the number completely/not been able to continue using it with his carrier.
I'd recommend that you reach out to your husband's carrier for further assistance with this.