Planning for the future, where to seek legal and financial advice?

Hello everyone, I'm a sibling of a person with early onset Parkinsons, based in the US. We are trying to plan ahead but have so many questions about disability, insurance, trusts, eventual long-term care, etc. We badly need advice from an expert, but we don't know where to turn. Does anyone have advice about who we should look for? Keywords to search for? Or specific recommendations for law firms or other resources? We are simultaneously dealing with my aging parents and their potential long term care, and it feels overwhelming.