Here is the book trailer and summary for Heavenly by Jennifer Laurens:
I met someone who changed everything. Matthias. My autistic sister's guardian angel. Honest. Inspiring. Funny. Hot. And immortal. That was the problem. What could I do? I did what any other girl would do-I fell in love with him. Zoë's sister darts in front of cars. Her brother's a pothead. Her parents are so overwhelmed; they don't see Zoë lost in her broken life. Zoë escapes the only way she knows how: partying. Matthias, a guardian sent from Heaven, watches over Zoë's autistic sister. After Zoë is convinced he's legit, angel and lost girl come together in a love that changes destiny. But Heaven on Earth can't last forever.