Hi Jan,
I knew that the post was a very old one-- I was very concerned that your brother-in-law might have given up hearing from anyone, but I'm so sorry to hear of his passing. My condolences to you and your family.
If you'd like to send me your e-mail address, I would be happy to send you a link to the family tree I've been able to map out thus far for the Garners. I will look for a "Joseph Christopher" on it, but I think it's more likely his dad might appear as one of Elizabeth's brothers, so you might recognize a name there.
I wish I'd been able to give your brother-in-law the connection he sought while he was still with us. I hope that this helps in some way.
Sincerely,
Beth