Wanting to be more involved

DH has a son from a previous relationship and since we live in a different state we aren't able to see him. However I heard that the mom and baby are moving back and since we never really got along (she didn't like the thought of me taking care of her son) we got in a big fight but I would like to burry the hatchet and I would like to be more involved in his sons life. I buy him all his necessities and more just because and send them to him. Do you think it is okay for me to contact the mother and ask if she would like to take their son and DH & My daughter out to the zoo or something? Would you feel comfortable