Before doing anything, send a formal demand letter by registered mail clearly explaining the situation and the deadline for him to pay his share - it's a document you're really going to want to have if this ends up in court!
That said, what people often forget is that even if your deed is super clear, legal timelines can be long and you might end up having to cover court costs yourself while waiting for reimbursement, so think carefully about whether it's really worth it before starting the process.
If he keeps refusing after the demand letter, then yeah you'll need to get a lawyer or bailiff involved to actually force him to pay, but honestly the emotional and financial toll before getting there is often more significant than people realize.