
Hi Guest
I also have a Staffy and a cat . He will occasionally chase her but in a playful way not an aggressive way .
A pup this young will see cats as a playmate and they see everyhting as a toy at this age.
Make sure the cats always have somewhere to jump to out of the way.
I would say "no" loudly when pup chases the cat- but with supervision there is no need for your mum to be worried . If pup is allowed to chase the cats then he will think he is allowed to .
They can live in harmony and I think its bad advice from your vet to say they cant :(