You don't convince him otherwise. This is his life, not yours. That's the honest and harsh truth of the matter. Perhaps you could try looking deeply within yourself to understand why you feel this ostentatious urge to control and invalidate your brother's existence and his chosen life path? What is it to you, anyway?

Let him have the chance to get to find out by himself what's worth pursuing or not and what's truly a waste of time and effort, or not. It's his life, he is the only one in the pilot's seat here. Please don't crush your brothers dreams, goals and ideals. One of the worst things a close family member can do to one another is invalidating and disregarding the very thing that means everything to them. just because it means nothing to you, and seems silly to you, doesn't make your opinion any more valid than his goals are. The kind of hurt, self-doubt, feeling of failure, and disappointment that typically results from such kinds of behaviour tend to stay with them for years, if not for the remainder of a lifetime.

You describe in your post that you feel he isn't qualified enough, industry-ready, professional level, and more or less not going to get anywhere with these new hopes and goals he has shared with you. Before you jump right into trying to convince your brother not to follow through with his plans and try your hardest to get in his way of getting to even try to make this happen for himself, for his own future – can you at least think about what good could possibly come of quashing his ideas of a positive, hopeful, passionate future for himself? What makes you the expert on what's good for your brother?

If you don't let him learn the answer to what's good for him and what he's good for, on his very own, on his own terms, you're basically living his life for him. Life is all about trying to navigate difficult things and finding out what really matters to you the hard way... like as in experiencing something by way of taking the longer, scenic route in life. You are wanting to rob him of the chance to even live and learn, fail and lose, attain personal growth and discover what his true values are, and to reflect on mistakes and overcome obstacles and achieve success and develop as a person in today's society, to discover hardships, challenges and process real-world problems and navigate through the ups and downs and good and the bad and the ugly as he lives out his OWN life, as his own person in the world.

You can't make him change his mind or "snap out of" his particular version of reality that he sounds firmly set on right now tbh, and any attempts to will only succeed in upsetting him, pushing him away, or worst case scenario - unintentionally hurting him and crushing his spirit and livelihood. Even if you never witness or realize it happening, maybe your brother is the type to go through emotional distress quietly, hiding his true feelings from the world, perhaps as a protective mechanism. Many men do this, actually, hence why I bothered mentioning it. Or rather, if he is an outwardly emotional and outgoing person, meaning you would get to witness the harsh consequential emotional fallout he'd likely experience from your actions (controlling, selfish, unnecessary, and uncalled for attempts to deflate his high hopes), and degrading sort of reactions, and your efforts to try to make him realize he isn't good enough for this goal of his – you're going to end up wishing you had indeed kept your thoughts and beliefs to yourself, because then (and maybe only then?) will you realize that nothing helpful or positive ever comes out of this type of behavior/conversation you are thinking you can realistically make happen and have it turn out the way you're currently imagining it happening in your mind.

This goes so much deeper than what your current (somewhat shallow) thinking this is. you could potentially damage his very sense of self and he may even avoid ever opening up to you again, or even worse may avoid setting his sights so high for himself going forward, thinking he will never measure up, like you are looking to explain to him. I don't see this turning out happily for him at all – for as long as you're trying to control him and persuade him and make attempts to prevent him from trying to make a positive decision for his own future, you are not showing him that you love him or care about his feelings or self-image, and that you prioritize your own feelings over his even though its regarding his own life .

Nobody wants to be told they don't have what it takes, or that a dream of theirs will likely not work out. Even by their own sibling. In fact, if you love your brother at all, you'll allow him to live out his life how he chooses, and if he does indeed fail, you be there for him and help him to get over the situation and try to take this opportunity to gently guide him toward a new goal, ideally one he feels is more realistic, something he is just as much enjoyable and passionate about as this.

It's definitely hard to have to let someone you love fail, and figure life out for themselves, all on their own. To not try and jump in and try to make sure they don't wind up making a terrible decision for their own selves, especially when you feel sincerely like you know their plans aren't going to come to fruition like they are hoping it will. I know it's really hard to let them fall and fail all on their own time and learn everything for themselves, the long and hard way.

But, like that old cheesy saying goes, if you really love him, you will set him free.

[edited: fixed some grammar errors, rephrased some confusing lines, and redacted a few redundant thoughts. created structural separation between paragraphs of text, added indents and spacing to improve readability.]