I don't plan on charging rental from him or his roommate. All I want is for the utility bills he/they used to be paid by them. We do vacation to Colorado at least twice a year for about two to three weeks (non consecutive) so I do plan on using the home for vacation also. Does that still qualify as investment property?
Welcome and thank you for your question. I'll do my best to provide an informative answer. Please let me know if you need any clarification.
This would qualify as a second home. The property taxes would be deductible on Schedule A as an itemized deduction. The mortgage interest would also be deductible on Schedule A, subject to limits (see Pub 936 here http://www.irs.gov/publications/p936/ar02.html ).
If down the road you decide to rent the home, you would then be allowed to deduct depreciation, along with taxes, interest, etc. on Schedule E. Until then, it would just be a second home.
When the home is sold, the gain or loss would be subject to capital gains tax rates.
I hope this helps and if you need further assistance please let me know.