Summer pudding wouldn’t be ideal, for me, on a couple of grounds – firstly, the fruit mixture may be sweetened and secondly the bread element. But, your T2 friend may not have issues with bread.
I’m not a great pudding hound, but we do socialise a lot and more often than not, I just pass on dessert. One of our few friends who knows I am diabetic thoughtfully made a deconstructed Eton Mess a while ago. That meant the elements were brought to the table, and everyone constructed their own portion in the proportions of strawberries, cream and meringue to their personal preferences. The group rather liked that, and it was interesting to see how individuals actually made up their dishes. On another occasion, she did something similar with very tart berries (raspberries, strawberries, red currants and cranberries) where the berries were presented “naked”, with side syrups (one made with sugar, and other sweetened with an artificial sweetener), and whipped cream. This was “marketed” to the assembled group as an homage to the figure conscious. As these people were mainly American, there are a few of those.
Small chocolate eclairs aren’t too carb heavy, and helped by a cream filling, if a non-berry alternative is required.
For me, I’m a very discreet T2, in that I don’t broadcast it. I will often pass on dessert, citing no room left, following earlier courses.