Most healthy Nymphalidae butterfly chrysalids like the suspended Comma you've found usually become active wrigglers when touched, often shaking the twigs and leaves nearby in the process.. The movement is unmistakeable.
One way to test if a butterfly or moth pupa or chrysalis is still alive is to test its temperature in a simple way. Place it gently against your face and if it feels cool or even cold, that is a sign of a healthy living specimen. A dead chrysalis can still be flexible around it's abdominal segments but if it feels warm with the simple temperature test, almost certainly it is dead.
Another butterfly which frequently breeds in gardens is the Speckled wood. Several times I've found their chrysalids suspended on fences or other parts of the garden in much the same way as your Comma. Like it's very distinctive larva, the Comma chrysalis is also very distinctive.
The Comma was the first butterfly caterpillar I ever found as a small child although I had no idea what it was at the time. Back in 1945 when I was three, in our East London garden, there was a massive old Elm Tree. Those houses were built in what some decades previously were farmland and that huge Elm was part of a hedgerow which formed the bottom boundary of the gardens. There were numerous 'sucker' like shoots around that elm and it was on one of those that I spotted that distinctively coloured larva. I clearly remember that the commonest moth there was the Small Magpie.... they were numerous ~ again I had no idea what they were at the time.
Although I was only three when WWII ended, I still have numerous vivid memories of the time. Not least that the weather was always fine and sunny and I spent much time in that garden. There's another vivid memory of that faraway time I am frequently reminded of every time I see a certain species of Bumble bee in my garden now. Back then as a very small boy, I saw one of these bees busy doing its stuff on the flowers in the garden and as nobody had ever warned me about bees and wasps, decided to pick it up by one wing with my finger a thump. Of course I was immediately stung and it was a far more painful experience for me then than any bee or wasp sting I've had since.... that first sting was exceedingly painful and I've had a healthy respect for these creatures ever since ...
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Surely if he hatches now its going to be too cold for him? 
