are you going to claim him as a charitable deduction? or a dependent? Since you lent him the place and made no income off that, then there is nothing to be done.
You received no rent so there is no income - unless he paid you in some other way. If there was nothing received from your friend there is no income.
If you have no income from this, there is nothing to report. You just deduct your mortgage interest and property taxes on Schedule A as you normally do.
If your home was a rental property and it was not rented for the period your friend used it and you did not receive income from the property during that time, then TurboTax should help you fill out that it was not used for business purposes for 100% of the year etc...
this is the base rule I learned from school tax advisor many years ago: no income, no penalty on not filing but good to file/report. For the rental prop, should be the same, anyway, not a big deal.
There is no simple answer to this question.
If this is your primary residence, and you were out of town and your friend did you a favor and performed house sitting duties for a relatively small amount of time, then you simply file as normal.
This may not apply, if this was for a "lengthy period of time," as such it could be considered rental property and business rules and regulations would apply.
If the house was up for sale during this period of time, and he was occupying the house to prevent criminal activity or squatters, different accounting rules apply.
If you normally rent the house out, but did not charge rent to a friend, then, depending upon the current laws, you may need to provide your friend a record of reportable income, as he is getting free rent from you. The rest of the expenses associated for the house is then considered a rental expense based upon current rules and regulations.
However, if the friend is "house sitting" for you in the event you cannot rent the house, then you should be able to expense the rent during that time, while providing the friend an equal amount of reportable income.
One thing to consider is that your insurance/rental/business efforts need to be in synch.
In your situation, I would obtain the advice of a tax accountant, and file for an extension. TurboTax will prepare your taxes based upon your entries. Correct entries may require the advice of a tax accountant.
You have to show it as a bartered income if he did something for you in exchange for the "free" rent. Like he maintained the property or did any other "free" service for you. What that value of his work is would be based on fair market value for that service.
If you simply gave it away, the only concern is if you did this in a manor that created a business loss for too long a period (three years?) as it could be construed as tax evasion.
Usually if this was done in good faith for a short term, you do not have to do anything.