As I see by my three accumulated Lactnet Digests, many people have told you baby can take breastmilk from a cup, if the daytime care giver is willing to do this.  Or with finger-feeding with an SNS type arrangement. 

Also, one dad, of whom we read on Lactnet,  found he could only get his baby to take a bottle if he tucked the bottle under his armpit, and wore his wife's bathrobe, so it seemed sufficiently like mom.

A  variation on this theme, would be have a stuffed animal, or something the baby can have next to him while breastfeeding, then have that with him while at home occasionally someone feeds him a bottle (of EBM), and then take it with him to the caregiver for snuggling against while bottle feeding.  Or maybe a tape baby listens to while feeding with mom, then played while bottle feeding, he will be encouraged that this is food time and food.

Another suggestion would be to position the baby on the bottle as much like BF as possible.  For instance, don't keep baby bundled in blankets and clothing during a feeding, and mimic the actual position baby prefers at breast, cradle, football, etc.  Also remember to change from right side to left during the feeding, just as the baby would at breast.   

Some moms have reported babies who absolutely refuse anything during the day, since mom isn't there, then breastfeed like crazy at night and on weekends.

Check the EBM for smell and taste.  Sometimes baby doesn't care about the smell, taste or temperature.  But if the baby is fussy, maybe change the temperature, or if it smells or tastes funny due to the breakdown of fats, heat it, which helps reconstitute it.

That's all I could think of off the top of my head.  

Sincerely,  Chanita, San Francisco