Nato issued a statement on the Ukraine and Georgia in 2008 and said they could eventually join Nato at some piont in the future.
A year later Nato stated that the reason for not opening the gateway to membership was unstable government, corruption / crime and unstable borders,
In fairness ,sadly events over the years proved they were correct at the time to be hesitant.
France and Germany in particular were against the statement, as they want neither to be admitted any time soon but as there isn't a bar on any country joining Nato ,(even Russia)
They could not just say it will never happen in those countries.
Both are in the Nato partnership for peace grouping , which means they work loosely with Nato in some aspects while not being members , lots of countries around the world are in that Japan ect,
None in that group come under the attack one attack us all , that Nato members have in place.
Nato is a defensive organisation , it main aim is to defend all of its members from attack by anyone, , there are no exclusions to that core statement , Russia / China included.
If it was as simple as not wanting to go to war with Russia , why have Poland ect been accepted?
personally I would ask to UN to saction no fly zones on humanitarian grounds ,
He would never accept it from Nato, but the very same countries would make up the policing of it in reality For the UN.
It would give people a chance to leave safely and would give Putin a bit of a face saver as he could spin it as we are not the enermy of the People and he is not the how he is currently made out to be in the west,
this gives him the opportunity for appearance sake which would fit in with his propaganda,
of not being against the Ukrainian people.
I am sure he could spin it for home consumption to look like some sort of hero.
Who cares what he says/thinks as long as the refugees from the war could leave safely.