Is this enough Milk to leave for baby?

Shalee 🦊

My husband and I are going out for about 7-8 hours today, and leaving our son with my mother. He's 3 months old and exclusively breastfeed, but does take a bottle (breast milk). I have about 20oz of fresh milk in the fridge right now, I'm hoping to get another 5oz before we leave. I'm just wondering do you think that would be enough fresh milk? I have bags of frozen milk in the freezer as back up, I would just prefer he have fresh.