How old is Frankie? Must be so difficult without a garden, something I take for granted so much. Gizzie is 9 months old and I think she goes that bit too often and often she is loose too. I certainly have to watch what food I give her and maybe this is the case with Frankie too? You could try experimenting with various foods? Not easy I know! I think that Gizzie shows too much urgency when she needs to go too, no idea if Frankie is like this? Gypsy Rose, her elder sister can and does eat anything!
Do you use pads for Frankie? We rarely use them here in the UK but if you don't have a garden I guess you have to! I can only guess that Frankie is young and I'm sure he'll gert in a routine. Best of luck, Ana xx