Where do you get the impression that this has anything to do with relations between the Mittals and Fernandes? There's absolutely no evidence of that whatsoever.
The evidence is that soon after taking their 30% share from Flavatore, the Mittals were quite involved in the running of the club and instrumental in bringing Warnock in for the first time. The family were evident at matches, not simply Amit Bhatia. TF came in and took over executive decision making, in hindsight, spending a fortune without much to show for it. Amit has slowly sunk into the background. I never see Lakshmi at games now. When an investor sells shares in a company, it generally means he's losing faith. It's not the personal thing necessarily, as suggested by your post
Again - I didn't think it's anything personal, or anything to do with them not liking anything that Fernandes is doing. All we know is that Ruben bought a chunk of shares from both Fernandes and the Mittals. So he's building up his stake, whilst the others are selling some of theirs to him. No motive has been indicated, and in fact when you look at the global Steel market, it's far more likely that the Mittals are figuratively tightening their belts as a result of their fortune being minimised. This is just an indication of that - nothing more as far as anyone can see.
Even when your fortune sinks to your last $10bn (which apparently is the Mittal net worth) you still won't feel too much need to economise I think TF and his partners are dominant day to day, and the Mittals are tired of being a side show, particularly when the club is treading water at best
Fernandes owns 55%. Of course he and his people are dominant. That doesn't mean that there's any more to it than that.
Look at the history. When Briatore and Ecclestone were suffering with a revolving door of managers, the Mittals came in and, by one major decision, turned things around. They wanted to buy the club but upset Briatore, so it went to TF and the Mittals stayed passengers for the ride. But the bus has stalled, and I think they're losing interest. That's just my view