Hello, you could pass a gameplay clip from your game. It must be incredible
Check his past posts, he included videos in literally every post he's made prior to this one, and on his old account too I recall. It had been kinda spammy early last year. The youtube channel is still there.
Regarding sharing source code:
For help to fix an issue: No. Helpers don't want to dig through your entire project to help you solve a problem in the first place, better to isolate the issue in a minimal project. By doing so you have a high likelihood of solving the problem yourself as well.
For publishing a game: No, a publisher should not need your source code to publish your game.
For porting your game to other platforms: Yes, the source code probably makes their job much easier and as a result cheaper for you as well. I wouldn't be too worried about them stealing your game - if their business is porting games, that sounds significantly more profitable than stealing source code and trying to pawn it off or sell it as their own, considering 99% of games are not successful and even less are blockbusters, while one instance of stolen source code would destroy their reputation. Taking into account you're paying them money to do so and a contract involved, they would absolutely be ruined if it was found that your source code for a game you paid them to port had been leaked. Not to mention you'd probably be richer by suing them than by any profits your game might have made. A publisher or porter would not likely risk their reputation and entire business on something like that.
If you want someone to port your game by recreating it from scratch, well it probably could be done, and most likely in significantly less time than you spent on the original code, but it would be expensive. But by then they would have written the code from scratch and they would have their own "source code" for your game by then anyway so what is the point. This is unlikely in any event, since the porting company would probably simply just not take your job if you don't want to provide your code, they have other work to do anyway.