Dear Ashely-
I am sending good thoughts and prayers to you and your little one Case.
My daughter had a series of heart repairs some years ago. I know how very scary it can be. Be sure to pack some things to keep YOU well and sane during his surgery and recovery...bottled water...healthy snacks...and something 'mindless' like knitting/crocheting/needlework to keep your fingers busy (I found I could never focus on reading).
Also...a change of clothes and toiletries...most hospitals will have a shower for parents to use...flip flops might be a good idea as well.
Nothing will prepare you for how he will look post heart surgery...but know...that over a few days...the 'tubes' and lines will gradually be taken away...
Kids are resilient! I wish for you peace...and send prayers to you all...Private me if you wish...you will be in my (our) thoughts!
Michele/cat