From my own experience of being the Jw and liking a guy who wasn't a Jw. He was a great guy in every way. I was raised a Jw by a mom who wasn't good at it but still dutifully took all the kids to meetings. I wasn't a complete JW because I had problems with the religion and I was "out" of the religion for several years.
But at a certain part when I became really attached to him, I also started backing off because he didn't believe in the bible. I let him go and he became the biggest regret of my life.
The thing with born in Jw's, is even if they are lax in the religion - it doesn't go out of them until they really see that it isn't the truth. Until then, they will try to get you to join because it means your eternal life. In subtle and big ways they will encourage you.
On the other hand
If the family is half baked in the truth and just slides along in meetings and such, they will bend the rules for themselves. But they will still have rules. And that might cause a low grade irritation and friction between you and the family including prospective husband.
Everyone is different and he might be a 22 mature person but .... he's playing games on the internet. Is this a first shooter game? A violent game? That's a big no no in JW land. So he is really not living a JW clean life.
Life is complicated and this will certainly be.