Why are we discussing a pop artist in the hip hop section? Let's talk about this but at least move it to the news section. Anyways, bacon, how can someone be a good parent for his kids when he's locked up? Sure, his estate may be paying the necessary bills and providing food for his kids' mouths, but is he there to tuck his kids in at night? Is he there to read bedtime stories to them? Is he there to teach them right from wrong? Is he there to throw parties for them? Is he there to scold them when they do wrong? Absolutely not. He's in prison and they get to watch what the media says about him and listen to classmates while they make fun of him for being in prison again. They have to sit there thinking to themselves, "well, daddy always teaches us not to do certain things, but then he goes and does them himself. Maybe those things are ok after all". It ends up being the American legal system, not their daddy, that teaches them morals by, in turn, teaching them to their dad.
As for you saying big deal to certain drugs, the fact of the matter is that 1. Drugs like meth, coke, and even ritalin do terrible things to your mind so it will impair one's judgment and so that alone is setting you up to be a failed parent, and 2. In this system those drugs are illegal, and so you have to be responsible enough to know that you will pay consequences for even having them in your possession.
Conclusion: TI is not a good father just because he talks the talk. On the contrary, he's a terrible father and he should be ashamed of the legacy he is leaving for his kids. He deserves ever minute he spends rotting in prison.