OP, I'm going to be brutal here - you need to snap out of it. All of this hand-wringing and wailing isn't helping anyone, and it's totally unnecessary.
Not all autistic children are non-verbal. Not all autistic children have severe learning difficulties. And even those that do, it's not the end of the world.
Autistic children are perfectly capable of being really happy and leading fulfilling lives, just like any other child. Many autistic people have deep and intimate relationships with important people in their lives.
It's a massive insult to be determined to think this is a huge catastrophe. It really isn't.
I have 11yr old autistic twins, a DD and a DS. My DS was diagnosed around the age of 3, my DD was finally diagnosed this summer when she was 10. My DS has a number of fairly marked challenges but he's phenomenal at maths and you won't meet a kinder, happier or more loving child. He showers me with hugs, kisses and "I love you's". Constantly. I am very close to my DD too. I genuinely couldn't wish for lovelier DC. I'm blessed.
My DS attended a special school - my DD was in mainstream but needs extra support. So much help and support from my fellow parents, and the SEN school. We are a close knit community. Yes, there are battles, but that's no different than any child. Our battles are just a bit different.
There's a saying "when you've met one autistic child, you've met one autistic child". They are all different and unique - just the same way all children are different and unique. Don't try and squeeze them all into a stereotype you've heard.
From your description, it doesn't sound cut and dried that he is autistic. But you know your child, a mother's instinct is often right. I have to say though, there are lots of positive signs there that suggest even if your DS is on the spectrum, his challenges may not be as severe as you fear. For example, he's babbling.
The single best piece of advice I was given by a paediatrician was to learn to view the world through my child's eyes. Put aside your own preconceptions and expectations. Years ago, I was wailing about my DS sitting under a slide for 30 minutes on his own, just looking at the sunlight filtering through the holes while all of the other children at nursery played. I was distraught. The paediatrician told me to get over myself - was he happy doing that? she asked. Well, yes.... Then why are you upset? she asked me. She pointed out that this was about his happiness and I needed to learn about how he experienced the world and what things brought him joy. It was the wake-up call I needed to stop feeling sorry for myself and to put my DS front and centre. To forget about what he "should" be doing - that's actually not helpful for the parent of any child! I spent lots of time over the next few years on groups listening to autistic adults, learning about what my DS (and unknowingly, my DD) was feeling, seeing and experiencing. It's given me great insight and I'm certain it's contributed to our close bond now. I get him, and he knows I am his safe space.
By the way, my DS was pretty much non-verbal until he was 5. He doesn't stop talking now.
Your family see a happy, laidback boy. And that's wonderful. And it's what matters.
You've had loads of practical advice - definitely get referred to speech therapy now, don't wait. Early intervention is recommended if your child is autistic. Keep language simple, use lots of pictures or props to go alongside language you use. Be consistent, be patient. Allow him to develop at his own pace.
But most of all, please just relax about this. Our families who include autistic DC are not living this disastrous existence you seem to think.