I don't know a lot about him, he is military. I know that he was dating someone a while ago and they broke up because she did not want to move to Poland...that's understandable.
I do know that he is very work oriented and has a difficult time relaxing. But when we do talk, it's always really nice and he smiles a lot.
I think you worry too much about him being from a different culture or him being a man. I think you should do what you'd want him to do. If you're hoping that he'll ask you out -> ask him out. Most of us men do not bite (unless you insist ;) and it's about time you leave the old school dating rules behind and do what feels natural. Once the dating becomes "official" we can easily unleash the gentleman that's lurking within all of us and chivalry becomes our second nature but initially some of us might need a gentle push in the right direction - yes, sometimes we're fairly clueless (or maybe it's just me?).
You say he's preoccupied with his work... well it could very well be BUT many of us, and I think men in particular like to bury ourselves in work when grieving past relationships. I know that my work (I have 2 jobs ;) was my savior after the divorce. It's been 2 years and I'm just now learning how to breathe again. He too could be "slow" in getting over his past failures.
Personally I think you can never go wrong with being kind to him, with showing an interest and maybe taking him out for coffee evey now and then. Sounds like you're doing all that so I say keep it up without being too intrusive.
Maybe a nice Christmas card with a greeting in Polish would make him smile. I certainly wouldn't mind getting a similar card from a lady and don't see why he would either.
Good luck to you, hope it works out...
PS. Don't by the "setback" theory in you having a child from a previous relationship. Kids are a gift whether they're "yours" or not. I've never ever heard any of my friends say "I like her BUT she has a child from her previous marriage." IF that's how he thinks (which I seriously doubt) then he isn't worth you, as simple as that.
Timed out in editing my post but the last sentence was supposed to say:
"...then he isn't worthy of having you as his partner, as simple as that."