Theo was concerned if he leaves you in Hogwarts alone your mental health would drop.

Since you joined the deatheaters you constantly had nightmares, hallucinations, episodes and even started starving yourself

Theo got the whole Slytherin gang to Italy except pansy as he didn't want her flirting with him all summer

Before Hogwarts ended Theo flew to Italy to child proof the whole house for you. Then send the tickets to the gang.