If someone takes partner to small claims court?

My child's father and I share a vehicle and he is on the title. He is only on the title because I had a huge down payment but no job since I left my job to be a stay at home mom. So I didn't qualify for a loan. He cannot make payments on a for sale by owner motorcycle that was stolen. Can the guy he bought it from take him to court or small claims (since he only owes $600 more dollars) and have a lien put on our current vehicle since we share it? Thanks.