6 week old kitten do not want to get off the bottle to the bowl

I have another kitten named frankie which is my best friend cat and he is from the same litter as my two cats are. Both of my two are weaned off the bottle except for frankie. I tried everything with the finger, spoon, even syringe the food in his mouth little by little and he spits out the meat but drink the milk which I ever seen before. I get that be is not ready but how long will he take into eating the food like the rest of the crew? He needs to eat to go home with his owner for she missed him much. She can’t donit cause she has to work and I do not want the kitty to starve while she is at work. He is very stubborn. Please help me here I need some advice