You could check if they can have lactose-free milk, which you can buy at the bigger supermarkets.
Oatly do a 'cream' that doesn't work in cooking, but works well when whipped.
You can buy egg and dairy free ice cream, which is nice with baked fruit, or a fruit sorbet.
You can make a crumble using dairy free marge, and add the oatly cream or the dairy-free ice cream.
I sometimes do 'caramelised oranges' in which I thinly peel one or two, and drop the peel in a syrup that I caramelise (100ml water to 120g sugar). I then peel as many oranges & clementines as I like, slice thinly, and decorate with the peel & caramel.
If you can get some nice dates or figs, they work well, and some people really enjoy having some nuts to eat.
My standard 'afters' is actually, cheese, celery & fruit.
If your guest is lactose intolerant, they may well be able to digest goats' or sheeps' cheese, but of course it varies.
PS: The lactose-free milk tastes just like ordinary milk, so easy to use up.
Hope you find something that suits!
