EBF LO——> trying to start nursing school

So I’ve stayed home with my one year old and 3 year old for the past year while going back to school online. My son is exclusively breast fed and has NO interest in milk from a bottle or cup. He will drink water from a silly cup. My son eats on demand, usually every couple of hours. I’ve tried to let family watch him for a little while and see if he’ll take a bottle or cup from them and he won’t. He gets fussy and just refuses anything of the sort. I’m not really wanting to wean him. Because I still plan on nursing him at night. Does anyone have tips on how to get him to take a sippy cup of milk while I’m at school?? My school is 45 mins away from where we live. So it’s not like I can stop by and nurse for lunch etc