Can we ask what kind of church this is? That might make a difference in how we answer you.
I will tell you this - I don't go to an Apostolic church. Our church has a benevolent fund. We have people come for help all the time. If they are already active in another church, we simply give the help. Period. That's it. If they are not active in a church, then we do ask that they attend at least one service after we help them. After that, it's up to them. We're not interested in prostelatyzing. Just in being good disciples
So it COULD be that they are not really out to win you over from your church to theirs. But we'd probably need to know more before we could say that confidently.
And I do think that you should be very upfront and honest with this pastor and let him know from the very beginning that altho you need and appreciate any help they can give you, you are very happy in the church you are in and do NOT plan to leave it. If you let him know that from the beginning, then it is up to him whether they choose to help or not.