Can you suggest ways to help my dog past the loss of her 'little buddy'?

Mmm.   Difficult one as one of our remaining two, sadly the younger one which knocked me back big time,  had to be put to sleep at the end of April.   They weren't apparently physically close - they didn't snuggle up together - but there was no doubt each reacted to how the other was behaving.  At first, she'd go check his crate which for some weeks, I felt unable to collapse and store.   Eventually I did as seeing her do this upset me big time, never mind her.  However, we started taking her with us when we went out so she wasn't left alone at home - or we didn't go.    I worked hard at trying to make up my mind whether to find another companion, an older one, for her but as the weeks have passed, she seems to have settled down and as she's 12.5 years now, have decided to let her have her final years without having to accept a new dog in here.  She did, with the one who died, after we lost her previous companion, but she was only just over a year old when that happened.    It's different now.

Sometimes our reaction sends messages to the one left behind and the fact she's mopey and seems sad, could be her responding to your vibes?   Only you'll know that.   So whether you decide to bring in another dog, bearing in mind there not be the same 'connection' (something I thought about before making my decision), is up to you.   It's easy to say buy, or adopt another, but this may not be the answer.

So sorry for your loss - it HURTS.

Yes an animal will pine away and mope around, not themselves. Try to give her lots of attention, go for walks, rides in the car. I would suggest another dog, but be careful, they should me on neutral ground several times and see how they get along. I would get a male, females can be very, very aggressive towards each other for dominance. I wish you luck, sorry for your loss. Good Luck!

 Treat her as you always did, nothing more or less dogs adapt very quickly... The more you pamper her. the more she will delay.

Get a puppy.  Obviously your dog needs a dog-roommate.

She's grieving. My dog was the same when our other dog died - overly clingy and needy. But after a few months she setttled back down. Just spend time with her, go for walks, do trick training etc and try to keep her routine as much as possible.

As for getting companions - it has to be the right time for you/your family and needs to be done safely to ensure any new pet is accepted into the home. A rushed decision now could lead to more problems later (not accepted, not having time to have safe introductions, you not being ready to have a new pet (some people feel it is "replacing" the old one)

She may need a new buddy, be it a dog or cat. Some cats are especially active, if your dog would get along with with a cat. Either way, she may need this company to be her old self. 

If your dog is eating `ok` , then there is not a lot to worry about.

She is possibly very bored now she does not have her companion to pass the time with.

I bet lots of nice interesting daily walks, especially in the countryside would perk her up a lot, and also give her a better appetite for her food.

Its not very interesting walking around a familiar yard by oneself.

I expect she relied a lot on the old dog too much, as is often then case when a younger dog lives with a much older dog.

Like people, dogs often have to get used to changes in their lives.

The more confident the dog or person,the easier it is to do so.

Get her out and about and around other dogs, maybe you have a friend who has a dog you can go walking with daily, her life has changed losing her buddy which she may have relied on more than you realised.

get another dog an older one  a rescue dog. SHe is probably depressed and lonely.

You can't. Dogs have to grieve in their own way just like people do, it takes time.

I lost one of my dogs in August as well, she died of heart failure, one of my other dogs that was very close to her has taken it hard, she is also mopey and obviously sad, she doesn't seem to want to play anymore, she does eat but barely,, she started sleeping in the other dogs bed so I haven't washed it because the scent is still on it,, she still walks around checking all the spots the other dog would lie in looking for her,, eventually she'll get over it,, it just takes time,, be patient with her just as you would a person grieving the loss of a close friend.

Yes people, dogs do grieve the loss of other pets, and people, in the family.