He college made a mistake on a 1098-T. shows scholorships/grants for a whole year but tuition for half. Looks like lot of income but isn't. How long do they have to fix it and forward to IRS?

As long as it takes to find the error, correct it, send the info to IRS. I am not aware of any time frame and would think the college would be in a hurry to correct the error.

You should contact your college for giving you amended 1098-T.
If you are a degree candidate and if the financial aid (includes scholarship and fellowship) is for tuition fee, other fees, books, supplies and equipment, then it is not taxable. For a degree candidate aid for boarding and travel are taxable. If you are not a degree candidate, then all the financial aid is taxable. http://taxipay.blogspot.com/2008/08/us-income-tax-topics-1.html