Apologies if this has already got a post here, I couldn't find one.
This sounds like a game you'll need to play with a box of tissues handy...
"After their beloved daughter falls ill, a family hopes to restore her health with the treatment she needs. Her caring older brother wants to help however he can and turns to the power of imagination and wonder to help take her mind off serious matters. While life appears dreary and cruel, the fantastic and surreal world conjured up by the children offers a wonderful reprieve."I've done a preview post about this game here:
http://www.indiegamenews.com/2018/09/heartwarming-adventure-my-brother.html
It's due to release on PC, Switch, PS4 and Xbox One on 21st September 2018.