1098-t income not showing in Turbotax

First, look at the output. Taxable scholarship should show up on line 8r of Schedule 1. 

You said, "His 1098-T box 5 exceeded his Box 1 amount substantially and it is all taxable".

Only the difference between box 5 and box 1 is taxable and that can be reduce by any additional expenses like books and a computer. 

Q.  Is there a place where I can enter that taxable income manually?  

A. Yes, in the download versions of TT. No, in the online versions.

What about the education credit? 

 There is a tax “loop hole” available to claim an education credit, for the parents of students on scholarship. The student reports all his scholarship, up to the amount needed to claim the American Opportunity Credit (AOC), as income on his return. That way, the parents  (or himself, if he is not a dependent) can claim the tuition credit on their return. They can do this because that much tuition was no longer paid by "tax free" scholarship.  You cannot do this if the school’s billing statement specifically shows the scholarships being applied to tuition or if the conditions of the grant are that it be used to pay for qualified expenses.

Using an example: Student has $10,000 in box 5 of the 1098-T and $8000 in box 1. At first glance he/she has $2000 of taxable income and nobody can claim the American opportunity credit. But if she reports $6000 as income on her return, the parents can claim $4000 of qualified expenses on their return.

Books and computers are also qualifying expenses for the AOC. So, extending the example, the student had another $1000 in expenses for those course materials, paid out of pocket, she would only need to report $5000 of taxable scholarship income, instead of $6000.

The IRS actually encourages use of this technique. From the form 1040 instructions: “You may be able to increase an education credit if the student chooses to include all or part of a Pell grant or certain other scholarships or fellowships in income. For more information, see Pub. 970, the instructions for Form 1040 and IRS.gov/EdCredit".  PUB 970 even has examples of how to do the “loop hole”.