I watched most of it. Nothing new, and he missed some points, which have all been addressed on this forum before. First, yeah, a 180A alternator can put out 180A, but for how long without overheating? That is why the conservative 40A or 80A limit for charging a large bank.
Second, a new alternator from Mercedes certainly has a temperature sensor in it, to limit output if it starts to overheat. So, thats the safety you need for a direct to LFP charging. Not all alternators have this. You need to know what you have before doing this.
Lastly, airflow around the alternator makes a huge difference. In an RV or van, the engine fan is moving tons of air, pulling it from outside, and cooling everything in the engine bay. Driving down the road at 60 mph, there is even more. Engines on a boat have no fan, and are completely enclosed, with minimal airflow to run the engine. So everything will get very hot. A blower can be installed with a hose to bring in outside air. That helps alot, but still isn't as much cooling as an RV.
Lots of people charge LFP directly from an alternator even on a boat. You just need to know if your alternator can take it, and if you need more cooling, or if you need to upgrade.