Amount of breastmilk oz for 1 year old

I will be gone on a business trip from Friday morning thru Sunday late afternoon. First time being away from my son. He nurses about 5 times a day (first thing in the morning, after his two naps, before dinner and right before bed.) But I don't know how many ounces he is getting. What amount of ounces of breast milk should I leave for him? He will be 1 year old at that time and eats solids as well. (solids 3 times a day: breakfast, lunch, dinner). Thanks for any advice. fTM here.