I don't have very good news for you as these are extremely serious charges.
On the pornography production charge alone, the state of Louisiana requires a minimum of 10 years of incarceration at hard labor up to a maximum of 20 years. There is no possibility of parole for this charge. And he would also face lifetime registration as a sex offender. You can see that statute here.
He faces two to 25 years at hard labor and registratin on the indecent behavior charge. See link.
And he faces at least 1 year up to 30 for the breaking and entering. Not only that but he could end up with consecutive rather than concurrent time for these.
I don't know the strength of the state's case. Sometimes, even on a first arrest, with charges this serious, a DA will not be interested in any kind of reduction of charges. In fact, if the case is strong enough, he may offer no deal at all and make your grandson either have to accept what the judge wants to give him (the judge does not have the power to reduce these charges) or take the case to trial.
He really needs a lawyer and to go over very carefully the strengths and weaknesses of this case. Because his lawyer will have a much better idea of what a good plea would be, being aware of all of the facts and having conferred with the prosecutor. But it's safe to say that his maximum risk if he's convicted of all three charges you've mentioned would be 75 years of prison, assuming that there's only one count for each of these. If he could package them all, anything in the 10 to 25 year range would be a reasonable plea bargain. By reasonable, I don't mean he should accept it. I only mean that it's well below half of the maximum and would be worth considering.