New neighbour moved in - could he turn into the neighbour from hell?

Yesterday a guy moved into the flat under me - by himself. So, sadly, it wasn't the possible gay couple I was told it might have been. I've not properly met him yet, only having seen him through the window. He looks to be in his 30s, but nothing in his mien makes me think he might be gay - but, of course, one can never be sure. He was talking to my next-door neighbours quite cordially. Then yesterday evening I was wondering why my two pussies were being so cagey about going in and out of the kitchen back window. I assumed it was just that they'd noticed a stranger, but then to my surprise and alarm saw a fully-grown Alsatian in the back garden. (Not that I personally mind. All animals are my friends.) But that was totally unexpected. Then I retired last night at 9.30, noticing that downstairs was in complete darkness so I assumed he was maybe out walking the dog. Then at 10 o'clock there was the sound of his coming in. The nights have been so sultry that I've been sleeping with all windows open with my bedroom looking out onto back garden. Then I got the smell of his smoking out there - and soon the 'nostalgic' smell of Amsterdam bars - grass being smoked. Although I've never tried it myself - not even smoked a 'normal' cigarette, actually (Ooh! Get her! 'Virgin Lips!' - at least as far as cigarettes are concerned! ;-) ) I've got nothing against cannabis smokers - loads of my past friends smoked it regularly, and I certainly didn't mind then. But with whatever combinations he was inhaling and probably imbibing, at first there was a mumble which grew and grew until his slurred words were discernible. I couldn't decide if he was talking to himself or to his dog - but the language was certainly 'colourful' - 'effing and blinding' loudly. That lasted for about an hour. He then went inside where I heard him bumping around - sounded like he was either knocking things over or falling down himself. For a brief period he had pop music on - loud! - then he went back to stamping and bumping around the flat. I was still awake at 3 a.m. I had to rise at 5.30 to put out the bins for collection. (I had feared I might be subject to a canine attack, having to enter the back garden to get the bins out. But I haven't seen or heard at all any signs of that dog since yesterday afternoon - so I hope he was only temporarily minding it for someone. Should find out today.) So as at this moment I've just got out of bed once again after trying to catch up on missed sleep. I've already heard him stirring about this morning. So I'm full of trepidation how this may turn out. He doesn't seem like the type of guy whom I could trust to care for my pussies if I'm called away. Meantime I'm hoping madly that last night was just an aberration and that he may turn out to be a nice, reliable guy after all - though the signs don't exactly look encouraging.