Old Omega needs a new winding button put on it.

Wow looks like it needs more than just the crown- if you want to preserve as heirloom it would need a full service- which may cost more than the value of the watch. Consult with watchmaker and consider if its worth it.

The watch can be restored, but it will be quite expensive, and the results may not be great. Just to be totally candid, it is in very poor condition. The dial has been poorly repainted, the lug holes are worn all the way through, the hands are not original, and the movement is corroded. Perhaps it could be preserved as an heirloom, a display piece, without necessarily restoring it to working order.

In principle, it's not difficult to fit a generic crown and stem to the watch. Many watchmakers would be able to find parts in their stash. It's a bit more effort to find the correct Omega-logo crown, but it doesn't sound like you care about that.

However, many/most good watchmakers are reluctant to do piecemeal work, and would say that the movement needs a full service. You might need to ask around a bit to find someone who would be willing to just install a crown. If you explain the context, regarding the fact that it's an heirloom and you want to pass it on to your grandson, a watchmaker might take pity on you.

TBH, it would not be a good idea to wind the watch and let it run without cleaning and lubrication. It will just cause further damage to the movement. So in a way, the absence of the crown is protecting the movement.

Yes this is an automatic winding movement so it makes sense that it will start running when it is moved. The oscillating weight moves back and forth and gears transfer that motion to wind the mainspring. However, unless you shake it around a lot, it should only run briefly.

Ahh this is a wreck. Perhaps some sort of desk top display. I’m not sure a watchmaker would take this on but….perhaps @sheepdoll would like a project….. ?

One of the bumper springs is missing as well.

The stem is probably not that much an issue, although if the plates are damaged where they have bearing surfaces then there is not much what can be done.

The service costs on this are greater than any intrinsic value. Pretty much the whole movement may need replacing. There may be some salvageable parts. This is not to say that such could be cleaned. The liability to do such work, is difficult in this day and age. There are threads on one of the top service people in the UK Simon Freese, who is having to deal with personal issues. Almost impossible for anyone to live up to the standards expected of a watchmaker.

Sometimes the only thing one can do with damaged watch parts is an art project. Perhaps a framed shadow box with other mementos.

If the grandson, is into watches, then they will know what is best to do. These watches do have the potential to last 500 years or more, when properly cared for. So there is also a potential for such items to have many stewards over the centuries.