Personally, haven had experience with people who are of a certain faith.
I would read him inviting you to his religious party, as saying, "i like you but I am Jewish, and we don't show interest in people outside of our faith, due to the complications it makes", and "I have invited you to my religious party, to see how you get on, and see how the rest of the crew see what your like",
and if you are really keen on him, then you may take religious conversion as a possible choice.
and then, you can hang out, perhaps with long term prospects.
He wouldn't be able to put the above in words, as it may make you either judge his religion, or worse still,
superficially convert to be Jewish so that you can hang out with him but not really convert in your heart,
which could lead your buddy to sin or in the religious folks perception, one of their flock breaking away from their congregation. Which to some religious folk is perceived the same as death.
I have been through a similar circumstance myself, and was the most psychologically traumatising experiences of my life. Worse that getting involved with hard drugs, you name it. Being caught in conflict with a partner who you love who is torn between you and their religion can cause nervous breakdowns and a great deal of stress from all corners.
Not something that I recommend.
I can not speak for the guy however, so perhaps it would be an idea to ask the guy,
although getting a straight answer out of religious folk can be difficult, due to the complex nature as stated above.
If the guy is seriously into his religion and it is not a religion that you can take to.
Then I recommend, as harsh as it sounds, to look else where.
As there are loads of potential partners in this world who don't have complex circumstances.
That is my advice on the topic.
If converting to Judaism is something that you would do, then, go for it. Explain to him how you feel and
be done with it. I wish you good luck!