Cuddles is Uber Dominant

Don't wish for it to be "over" because that will mean one of them is gone.  Learn, instead, to live with it.

First -- you have to keep things in ORDER.  Dogs need routine and they need some sort of pack structure to be respected by the humans.  When you have one dog that is elderly and small, THAT dog is not the alpha.  don't treat him that way.  *****INSTEAD***** treat him with respect. 

 That IS different.  Let the youngster be "first".  That means you feed that dog first, pet it first, etc. 

But that does *not* mean you can't lavish special attention on Brownie.  Just don't set him up as a target.  If a young dog thinks you don't 'get it' -- that the old guy is not alpha/protector/strongest and the OLD dog is past caring (hence he is willing to get down in deference to the younger dog) -- then the young dog will go out of their way to make an example of the older dog. 

It's as if they think you don't "get it" and so they continually demonstrate TO YOU behavior that says to them "I'm in charge -- don'tcha understand??"

 Don't confuse a human definition of "fair" or misplaced loyalty "But Brownie was here FIRST -- he should be first in everything" -- that's just plain wrong.

Let Brownie get to the door -- and then you humans take charge of the situation.  Either pick Brownie up, or gently help maneuver him to the SIDE.  let Cuddles and everyone younger OUT.  They're younger, stronger and more reckless -- let them thunder outside.  THEN help Brownie out.  If you can't buld a ramp for Brownie, then how about getting some wood scraps to make smaller steps.  So he doesn't have to jump down off a high 3-4 steps -- put blocks of wood down to make 6-8 smaller steps for Brownie to go down.  Or just build a ramp for half the width of the stairs.

But let Brownie go LAST.  It's safer -- no one waiting to pummel down on top of him.

I'll give you a clue -- when you are arthritic DOWN is harder than UP.  Down is sharp impact on your joints. UP uses strength -- get your front feet up and them PULL yourself up.  So give Brownie time and space.

Get Brownie his own cushion (you can make such a thing if you want).  IF Brownie wants to get up on the sofa, fine -- but make sure that cushion is on the floor next to the sofa so Brownie can jump on that rather than to the floor.  Teach Brownie how to do this.  Encourage him to lie ON the cushion - they are really better off not being 'up' on something high enough to hurt them getting down.

Now as far as Cuddles body blocking Brownie -- don't let it happen.  Clip a leash on Cuddles and leave it on while he's IN the house.  If you see him begin to move towards Brownie just step ON the leash and prevent it. 

But if Brownie is up on something and Cuddles comes into the room -- defuse it -- call Cuddles for some attention and then if Cuddles makes a move to try to push Brownie around hold back on the leash and just plain don't let Cuddles close enough to do something.

Remember - ultimately you humans are the pack leaders -- YOU make the rules.  Just don't set the situation up so Cuddles feels like he has to move the old guy "down" over and over and over.  When you want Cuddles to leave Brownie alone SAY SO.  "No Cuddles -- leave Brownie alone"

I've got one VERY elderly peke (Kee Shu) -- she's always last ... shoot it takes her forever to GET anywhere.  But we always make the others stand back and not get rough with her.  We teach them 'gentle' and 'stay back' commands to keep them out of her way.

I think, first of all, you need to lose your ideas of status with regards to the dogs. 

To be honest, a dog that barges out of doors and appears to want to be "first" at everything sounds like a young adult with little impulse control, or possibly a beta dog who just WANTS to be alpha.  Also, an small and elderly dog CAN still rule the roost and can do so with little more than a Look - I've seen it.

Plus (and this part is IMPORTANT) - it really doesn't MATTER in the scheme of things, if Cuddles is "above" Brownie or below him.  It is irrelevant.  What matters is that YOU are "in charge" and that BOTH dogs respect that - in other words, they will both take direction from you, when it counts.  In this way you can give Cuddles cues to pre-empt any behaviour that might hurt or frighten Brownie.  Am I making sense?

What I am getting at is that you really don't have to try to guess which of the dogs is or should be "first" - and it's not always a good idea anyway because it very easy to get wrong.

Implement NILIF and dole out meals and priveleges on the basis of BEHAVIOUR and the demonstration of IMPULSE CONTROL - NOT status!  In other words, first to sit is the first to get a treat.  The one who waits patiently gets petting and attention while the one who jostles and barges rudely is calmly ignored.  Be assured that the "rude" dog will quickly learn to control himself in order to get the goodies that his buddy is getting.

Agree with Chuffy.  I have a bossy, bossy little terrier. If he had his way, he'd barge in front of other dogs, dictate what they can and can't do (in his perfect world, they'd just stop stealing his air! :P) and so on.  But that just isn't allowed here.  Everyone sits for treats..if you try to take another dog's treat (and Aesop is king of the 'I will drop my treat so I can break itty bitty pieces off and savor them', so he's lost a few treats), you're getting put into a sit or down stay while everyone else gets theirs before you get another. Pushing another pet out of the way for pets won't fly either.  And, as much as he's a bossy guy with other pets, he's all about rules, and he picked up quickly what was expected.