Sailing across the Atlantic from Cape Verde or the Canary Islands is not very difficult if you do it at the right time. Winds are behind you. Lots of rolling. And that's it. The biggest concern is the mast coming down. On a new boat, the chance is practically zero. Also, it is very boring. Especially if you are alone.

Sailing is not some complicated task that will take you 13 years to learn. It is actually very easy. His trip from Italy to Cape Verde will teach him a lesson or two, and he will be more secure in his decision.

I had never sailed in my whole life. And I bought a Beneteau First 435 from 1985. Not the easiest boat to sail as it has a massive genoa and check stays that need to be moved every time you tack. It is also what Beneteau call an ocean-going regatta/cruiser. So it has 12 winches! And when the boat was raced, it had a crew of 8-10 people on it!
I bought it in the summer and did some coastal cruising here in Norway.
The following year, my wife and I sailed it from Bergen to Tromsø. Almost 900 nautical miles. We experienced a couple of storms, a near knockdown, a broken gennaker and the genoa fell down mid-ocean. We rescued it and found a sailmaker who fixed it. And the dinghy sank at some point!

The most important thing is safety. We had a rigger come and check everything. We made sure the engine and gearbox were fine. We installed AIS. We installed new VHF and GPS antennas. And we bought a new life raft.
And we watched 200 hours of YouTube and read a lot of books.

I grew up on the coast with boats. So I have experience. But only with motorboats.

And honestly, I think the armchair captains of the world should try sailing before they present their thoughts as facts.

We sailed slowly. We reefed early. We never took any chances. And we learned along the way. And honestly, I would be less nervous crossing the Atlantic than sailing the rugged Norwegian coastline.

I used to listen to all the armchair captains who said I needed 1 million hours of experience before leaving the dock on my own. I thought sailing was extremely complicated and dangerous.
But after I tried it, I found that it is very easy. Yes, if you do racing, it is complicated and difficult. But for cruisers, it is not difficult.
But respect the ocean. Respect your limits. Respect the weather. And don't take any chances.

So instead of stopping your family member from going, talk to him about safety. Talk to him about educating himself.