Need advice.

The father of my baby claims to want to help support our child and wants to be involved as his father, but has yet to do one thing for either of us. I have gotten literally everything except for a high chair. I didn't see it as a priority because baby won't need it for a few months. How can I ask him to buy it? I've payed for medical bills and all of the baby's stuff so far and think he needs to do something to help out.