While it does qualify as a 2nd home, you can't claim the tax credit unfortunately. See https://www.irs.gov/credits-deductions/residential-clean-energy-credit under the section "Who Qualifies?" The second paragraph states, "You can't claim the credit if you're a landlord or other property owner who doesn't live in the home."
It further states, "You may be able to claim a credit for certain improvements made to a second home located in the United States that you live in part-time and don't rent to others."
Being that you can't be living in it part-time if someone else is living in it full time, You would not qualify for the credit.
