How should a family gift toward a primary home purchase be handled before private school/college financial aid reviews?

My family may be facing a complicated financial aid / family gift question, and I’m trying to understand what professionals to consult before making any decisions.

A widowed parent may want to help an adult child’s family purchase a primary residence in a very high-cost-of-living area. The family currently receives need-based financial aid for a child’s private school tuition and will eventually also need to understand college financial aid implications.

Before accepting any gift, we want to understand how different structures could affect aid eligibility, including:

1. A direct cash gift toward a home purchase
2. A parent buying a home and allowing the family to live there
3. A trust distribution or inheritance advance
4. A loan or partial loan
5. Any impact of home equity, cash assets, or large gifts on private school aid, CSS Profile schools, and FAFSA

We are not trying to hide assets or misrepresent anything. We are trying to comply with the rules and avoid accidentally making a decision that creates long-term financial consequences.

What type of professional would be best to consult first — financial aid planner, estate attorney, CPA, fiduciary financial advisor, or someone else? And what questions should we ask them?

I’m intentionally keeping details general for privacy. Thank you for any guidance.