I would get him a dog.

I would also set him up on Skype so that you and your sister can interact with him in a personable way more often.

This is actually a great suggestion. If you are a dog person it can bring a lot of joy, amusement and companionship. The thing that sucks though is that they very short lives. My lhasa apso did live to be 17 years, but this is unusual for most other dog breeds.

About loneliness and losing people dear, my brother's friend's dad lost his parents, wife and son all at an unusually early age. I would have no idea how to deal with that.

I also agree with this suggestion. I know that battle grounds are drawn on the dog vs cat debate, but either/or would do well for most lonely people. My wife's grandfather died when we first started seeing each other; 5/6 or so (oops - I hope she isn't reading) years ago. Bizarrely, this was within a few months of his dog dying. He took that thing everywhere - snook him into hotel rooms, family houses, the golf club, trips abroad.

Part of my commute involves walking through a public park and I've noticed that the people out walking their dogs seem to find it much easier to strike-up conversations with each other thank other park users. I'm not a dog person, but a dog might help Xcelerate's father make new friends, or at least acquaintances, as well as providing companionship.

Really fantastic suggestion.

Dogs are amazing companions, however the long hours he works probably don't help, however he's probably working long hours so he doesn't have to come home to an empty house.

I agree it may help, but how on earth is a dog the same as a companion? It will fill a different void but certainly not the lack of a soulmate.

It's not. But it exposes one to many social interactions by walking, grooming, vaccinating a dog etc.

add a social hobby (e.g. golf) to that list for some out of house time

My father died 7 years ago after my parents had been married for more than 50 years. After a few years of solitude, my mother started to develop a whole new life (with 80). I think this will develop also for your father, it just takes time. But he has to be ready for it and there is little you can do to accelerate the process. Maybe he was busy with you and your sister until recently?

Key for him is to leave the house. Go to the doctor, buy fresh food on the market instead of in the mall and chat a few words with the farmers, join sports teams (my mother did when she was 78) or meet with colleagues for a beer (they all want an excuse not to go home, believe me).

My brother and I also live far away. That is not a problem (as long as he is in good health…), because it assures that your father has to manage his life for himself instead of sitting down and let you organize it. Also make him visit you instead of the other way round. This will let him leave the house, see different towns, revive his interest in life and discovery and he has to make plans (this is important). It worked for us, at least.

Where I live, also the church has groups for tea/coffee and cake. So has the red cross. This may aim at older people but it is great to go there. My mother loves it. (yes, I know, she is a woman and women make contacts easier). But, as I said, some day he will be ready.

I'd suggest him picking a hobby, and taking classes about it. He doesn't really need someone to date, apparently, but just someone to talk to and have fun. Going out and doing something he likes surrounded by like-minded people sounds about right.

When my dad retired he started participating in local organizations, like the Lions Club and a food kitchen. There may be groups, organizations, meetups, etc. that would help your father establish some meaningful relationships outside of work.

Just have him move with you. It's a priceless experience.

I've been thinking about doing this in the upcoming years. I'm guessing you're speaking from experience, if so, can you elaborate more?

Make sure he knows that dating doesn't mean he's trying to replace the relationship he had with your mother, or take away anything they had together. It's possible to meet new people, have new experiences, and still cherish those old memories.

I'm not sure where you are located, but back home in Australia they've come up with the idea of "Men's sheds". I think it's a great idea on so many levels.

http://www.mensshed.org/what-is-a-men's-shed/.aspx

I'm not sure if it's the kind of thing your dad would be into (my dad probably not). But sounds like fun.

My mom goes on vacations and city-trips with loads of different people. Some of those people she still has contact with, but even without that the trips themselves are a welcome diversion.

On the other hand, it's not your responsibility to arrange for your dad what you think is best for him. He's an adult and will try to make the most of his life and will succeed or fail to be happy on his own.

I'm a father and I wouldn't want my kids to patch my lonely life if I have one: they have their own lives and I have mine and it's certainly nice to see them sometimes but it can never be a deal breaker.

It's not OP's responsibility - but love is love, and wanting the best for your parents is not a bad thing at all.

Actually, I would consider that making it my responsibility. I love my father. He made sacrifices for me, I will return the favor if I have to.

The OP can't "make" his/her father do things, however they can suggest things. They implied the father wants to/is open to new experiences.

I don't know how old your dad is but I suggest he go to the local senior center.

create a profile for him on match or some other dating site, and organize some good dates