It's been 6-7 months since Twiggy has seen a vet - T4 was checked in the past..
Will try the nighttime - play/snack thing to see if it helps.
Will also try the rescue remedy thing -
As far as I know nothing has changed for them...she tends to make this sound in the livingroom on the floor - she is not looking out a window or anything.
It is possible that she is calling her brother to play...but he's sleeping cuz it's the middle of the night.
Food dishes would have to be high tech in my case because any food release would be gobbled by baci, the other cat.
many thx for the suggestions here