You need to sit down, shut up and stay in your own lane.
It can be hard to be a new immigrant to a country, even if the immigrant thinks they know the new place.
I was 40 when I moved from Vancouver (where I was born and raised and grew up watching the likes of Coronation Street, Goodies, Fawlty Towers, AbFab, Are You Being Served, Smack the Pony, etc on telly... hell, I even remember Button sodding Moon on t.v. back in the 70s) to London to marry my DH and I found parts of my new life to be confusing, in spite of how much I thought I 'knew' my new home town.
12 years on and there are still the odd times when I'm befuddled by life in the UK.
I can only imagine how your DiL fared when she first arrived, what with all of the 'sees' that she's seen in her young life and the language barrier... if a de facto British person (as a Commonwealth citizen, I had most of the same basic rights as my England born husband, except the right to a passport, when I first arrived... that took 4 years and a small fortune in visa/naturalisation fees to achieve) like me can be confused and overwhelmed then imagine being expected to cope with a new family in a foreign place and in a language you might not speak/understand very well.
As for the grandchildren, just be glad you're able to see them as often as you do. My own MiL sees my DD (8) 2-3 times per year (she lives in the North) while my own parents see her every few years, as it's not exactly easy (or economically viable) to be jetting off 9+ hours to the west coast of Canada each and every school holiday.
As much (or, as you'd probably judge - as little ) as my parents and my in-laws see my daughter, they're most certainly not excluded from her life. Husband and I send 'the grandparents' regular updates and photographs and video of what she's up to (she was camping with her cub scout troop recently, so we sent photos from that... we send copies of her report card from school [I'm ethnically Japanese, so it's an unspoken expectation from my parents that they get a copy of her academic progess] etc etc) and we chat with each other via FaceTime and WhatsApp.
You're going about things the wrong way, OP... it's good that you're worried about your DiL taking the kids to the Ukraine... I'd be worried too, but you've got to lose this attitude of self entitlement and 'Mum knows best' because it's not a good look... if you could be a little more welcoming and dial back the judmental aspect of how you see your DiL, you might find that your son and her are a little more amenable to visiting.
Just something to think about.