My dad was used by a younger woman—how do i help him?

My dad started dating a woman 25 years younger than him. She moved in with him, and while my family was initially skeptical, we decided to accept their relationship.

She had two children back in her home country, and my dad went above and beyond to help her. He bought her expensive gifts, sent money to her kids, and even helped bring them here. He paid for their travel, signed papers so they could live with him, and once they arrived, he bought them new phones, clothes, and even took them on vacations.

Then, about a month ago, she told him they were moving out. She’d secured an apartment through the municipality. And just today, I saw her holding hands with another man.

I’m heartbroken for my dad because it’s clear she used him. He’s devastated, and I don’t know how to help him move forward. How do I support him through this? Any advice on how to help someone heal from such a situation?