"Appease" is not a word I would use in this context. The Glazers have humiliated the club they legally own and the shitstain on our reputation as a club cannot be erased.
But if the question is what can the Glazers do in the present and future -- two separate questions, as we're in a crisis at the moment so the present must be dealt with, but the structural changes have to take place to secure a better future for the club -- it's complicated. I run a small business so I know fukkall about running a massive commercial enterprise like Manchester United, but I do know that the Glazers must genuinely acknowledge that their focus on short-term profits and indifference to the quality of the "product" on the pitch has put at risk future revenue growth of the club.
We can debate for hundreds of pages what the Glazers need to do, but right now they need to back the manager, even if it means spending more than they would like to, and even if it means going with no-name players instead of galacticos. I'm not suggesting we should avoid galacticos, but whatever the new manager believes he needs in terms of squad improvement, improvements to behind-the-scenes aspects of how football training and development is conducted, the Glazers have to back him. They can't stuff a player down the manager's throat. If, for example, ETH wants Casemiro and a deal for him is a real thing (which I doubt is the case) then let's get it done. That doesn't mean the Glazers should spend 500m on players ETH wants to make us happy, but the checkbook does need to be opened to some degree if ETH has identified realistic targets that meet urgent needs.
But this thread implicitly asks a much deeper question, which warrants a deeper discussion. But right now we have a September 1 deadline to focus on to either get the squad into a position where it can compete for fourth place and maybe win the EL cup this season...or build a foundation for the future that will begin to pay pay dividends next season but force us to accept a 7th or 8th place finish this season.