ADVICE! My partner thinks I’m overreacting!!!!

My Grandma has recently found out she has liver cancer and a few weeks to a month to live. We live 5 hours away from her and all i wanted to do was go be with her. I asked my partner if he could take 2 days off of work (Thurs, Fri) to look after our kids whilst I spend the weekend with her without my kiddies being full on (they always are when they’ve been away from home too long), to which he told me he couldn’t afford to have days off, AFTER he spent the week before off JUST TO PLAY FORTNITE 🤦‍♀️. I just told him not to worry, I’ll take the kids like I do everywhere I go and he can carry on working. We left on Thursday morning and come to find out this asshole came home from work Thursday, then went to a mates house and got drunk, had Friday off of work because he had a late night and was hungover. WTF! I’ve never been so mad, especially when it comes to me wanting some quality time with my grandma before she dies, I’m glad to took my kids they were well behaved but for him to do me like that! It’s been a week and I’m still as pissed off as I was the day it happened. He doesn’t see anything wrong with it because it was his ‘cousins’ birthday and he ‘had to drink’!!!!!