Mum has nasty neighbour

[crackingon]

Not sure if this is in the right place to post this . Mum is 68, lives alone and has been in same house for 40 years. House next door is rented so people come and go. Woman moves in with small child - everyone gets on. Boyfriend then moves in next door and brings pets, couple of dogs and 3 ferrets that live in the garden. There is a no pet rule for next door and mum doesn't mind the dogs - but the ferrets are kept outside , and the smell from their cage makes it impossible for mum to sit in her very little garden. She calls the letting agent who are not happy that he has any pets and says they will sort. Well now the boyfriend is making snide comments every time he sees my mum and she is getting anxious. She feels if she says anything he is likely to do something to her car or house (he hasn't so far ).
My question is what would you do ? I want them all to get on but that's obviously not happening

If she is being threatened I would suggest you install some cctv, with sound if possible. It will prove harassing behaviour and your mum can take the evidence to the police.

They sound like bullies and I feel for your mum.

Not a nice situation, but it's quite a jump from snide remarks to vandalism and violence - does your mum have reason to believe it's going to go further? have any threats been made?

She did exactly the right thing though.

Thanks for replies , no he hasn't actually threatened her as such. Things have been knocked over in her garden overnight ( that are too heavy to have been blown over ) . When he comes into his garden he says things like " oh hope it's ok to come out here ... Hope I'm not upsetting anyone with by being here " ( in a loud voice ) . Mum ignores but then feels she can't sit in her own garden