We have set up SSRS service application in our farm and we are able to deploy ssrs reports from our SQL server which is attached to the farm and this SQL server has SSRS installed in SharePoint integrated mode which was a pre-requisite to  have ssrs with SP.

Now we have another user who is in the same company (same network) and his team has a SQL server (not attached to our SP Farm)  and he wants to deploy reports to his SharePointsite hosted in our environment.Should he also need to have ssrs installed in SharePoint integrated mode inorder to deploy to the site in our farm ? If so can his SQL server have SSRS installed in both Native and SharePoint integrated mode at the same time ?