If you're eating a substantial protein source at dinner (e.g. beef), having a meal before you hit the pillow really isn't going to make or break anything. As stated earlier, if it helps you sleep better, go for it. If it feels forced. I'd opt not to. In either case, make sure you have your
macros worked out to include ( or exclude) it in/from your diet.
You damn nutrition guys calculating everything again (still)
Milk protein is part whey, part casein (not equal parts however). The casein is slow digesting, the whey obviously isn't.
Tis' why some people consider milk a 'perfect' food, once you consider the complete macro profile (of whole milk).