His friends would probably take care of him. Midoriya would be very eager to help, using his kind-hearted nature. He would make sure Todoroki is fed and comfortable.
Todoroki's character development in time travel fanfictions can be quite profound. He may start as a somewhat aloof character, but through time travel, he begins to understand the importance of relationships more deeply. When he travels back and witnesses the relationships he could have had or lost, it makes him cherish the ones he has in his original timeline. His view of heroism also evolves. He realizes that being a hero isn't just about using his powers but also about making the right choices at the right time, which is especially highlighted when he has to make decisions that could change entire timelines.
There could be a moment where a character saves another during a Quidditch match, not just because it's the right thing to do but because of the love they feel. The wind in their hair, the adrenaline of the game, and the look of relief and love in their eyes as they hold each other in mid - air on their brooms is a really romantic moment in Harry Potter fanfiction.
My own 'first i love you' story was when I was on a hike with someone special. We had climbed to the top of a mountain and were looking out at the amazing view. The fresh air, the beauty of nature all around us made me feel so alive. And I just blurted out 'first i love you'. It was a bit scary at first, but it was also very liberating, and luckily, they said it back.