They're bankrupting Angenas. That's not him helping. That's him tying the noose. Grandpa might wanna play the longer game but Perez asking for a fine when Angenas is floundering at the loss of the head of the family is gonna make them even more desperate. I think it's a game of pros and cons. Perez choosing a potentially more dangerous route fits his character. Lombardi grandfather is more of a plan ahead kind of guy. His plan might have taken longer but it would have hurt them deeper. Still, the outcome of this meeting was hitting two birds with one stone. Angenas lost money and is shamed for causing the accident that killed their patriarch. Win-win.
Don't worry about it. Grandpa was also annoyed after all. His plans are usually the same with Tia's but she's more flexible when it comes to these things which is actually funny. Tia would understand Perez's plans better than Rulac but she would also understand her grandfather's frustration with Perez. She dotes on them both and I'm not sure she realizes just how much she spoils the two men.
So why are you helping them my guy