This is a difficult situation for all concerned. I am sure that Tiffy is quite confused and wondering where her human is. I have a quiet area for Ricky that is just off the kitchen. It is a little hall way that leads to my laundry room. I bought a baby gate at a thrift store for $4.00 and put it up with Ricky enclosed. He can still see everyone and feels like he is not alone but it gave our cat a chance to do what they do without him pouncing on them until he got more used to "rules" and commands. I also used a lead to keep him in check. This is a learning time for Tiffy so be patient but keep your cats safe.
MHMama