The government (and society in general) should stay out of other people's business w.r.t. their autonomy in this matter. People should be free to decide if they want to end their lives with dignity.
I'd say no, of course not. You tell them it's a bad move. You don't give them a lift to the bank so they can withdraw the money.
I wouldn't advocate breaking their arms so they're unable to sign the paper work but there has to be things you can do short of watching them ruin their lives (or actively helping them), right?
Most places have a blanket prohibition on assisted death, which seems more authoritarian to me.
A dignified assisted death means you end your life on your terms.
I wouldn't call suicide an improvement over proper treatment or social help. And we're not talking a terminal case here.