Most people can't do this for a variety of reasons.

Mine is an autistic kids. This isn't really good advice, it's basically an empty platitude.

Find meaning in your life is actually what the 2 of you are telling him. Traveling is super overrated and is not an ends to itself.

Without meaning, there isn't much point to life.

I would say that travelling on a super low budget (or no budget at all) can be a transforming experience. It forces you to interact with locals to obtain any kind of food and shelters, and to live their lifestyle (because you can't afford anything more comfortable). On the other hand, I don't see much value in travelling where every discomfort can be removed by just opening up your wallet. It's nice but no essentially no different than going to the mall and movies in your town.

100% this. I went traveling searching for meaning in my mid-20s. The most important lesson I learned was “Wherever you go, there you are”

Exactly!

I'm sorry to hear about your kid. I don't know about your situation to give you any help. Most of the people have no valid reason at all, they imagining the chains that are holding them down. There is not always meaning in life, sometime you can just go with the flow and still enjoy life. Travelling is not the answer to everything but it will make you a lot happier if you do it right. It's the not the Destination, It's the journey -- random smart quote.

Your reply I'm sure won't be the most popular with the younger generations, but this is more realistic.

edit: A sabbatical may be a good idea in the OP's situation and need not always mean travel. Could also be a pursuit of arts, further his interest in physics etc.

I think it's a mindset. People want meaning in their life, I wonder if it's because they are bored. I have travelled a lot and I had no meaning in mind, just went with the flow, no plans at all, just places I knew I wanted to go. I can't say it's the solution for everyone, but for many it will do you good.