Can a finding from a child protection court affect who gets decision-making responsibility later?

Yes, indirectly. A finding made in a child protection case - for example, that a child was in need of protection because of neglect, abuse, or exposure to family violence in a parent's home - isn't itself a family law order about decision-making responsibility, but it can become important evidence in a later or ongoing parenting case between the parents. The best-interests-of-the-child test that governs decision-making responsibility and parenting time looks at each parent's ability to care for, and safely make decisions for, the child, and a protection court's factual findings about what happened in that parent's home are relevant to that analysis.

The family court isn't bound to reach the same conclusion the protection court did, and it will look at the current situation, not just the historical finding - has the parent addressed the concerns, completed any recommended programs, or changed their circumstances since. A protection finding also doesn't automatically mean a parent loses decision-making responsibility altogether; the court can still consider more limited responses, like restricting a specific area of decision-making rather than removing it entirely. Bring the protection court's findings to your family law lawyer's attention early.