Okaaaay so since I’ve seen a few comments asking for an explanation: No, Maria is not dead or an illusion/Yes she still has her heart condition. Maria’s health is like a bit of a rollercoaster (like mine) and she can go in and out of the hospital— to which when she is in the hospital, it causes the most anxiety for Lucas. Maria is naturally a very hyper/silly gal and she tries to not let her condition control her life and how she behaves (as safely as she can)
I’m going to explore a lot more about why Lucas blames himself for her health later in the series (a lot in season 2 if I get approved for a second season) so just stick along for the ride :) talking about this sort of stuff to anyone will take a lot of time for Lucas, even with how close Thomas and Lucas will be later on the season