It’s people misunderstanding the term ‘energy’, and wishful thinking making them think ‘energy never dies, it simply transforms’ is a comment on the ‘soul’, not physics.
Think of it like this, people who are confused. When you charge your mobile, you put electrical energy into it, which is converted into chemical energy stored in the battery, plus some given off as waste heat. When you use your phone, the chemical energy stored in the battery is converted back into electrical energy which powers the phone, again with some given off as waste heat. If you measured all the energy that has gone into your phone and all that comes out, it will the same — that is what we mean by energy not dying but being transformed.
It’s not a handwavy ‘spiritual’ statement meaning an individual human consciousness continues in some form beyond the death of their body because their soul escapes as ‘energy’.
When we’re alive our bodies derive the energy they need to fuel their processes from taking in food, their own fat stores etc — chemical energy becoming, say, the electrical processes of the brain and nerves. When we die, different chemical reactions start breaking the body down as food for other organisms to fuel themselves via decomposition, and our heat dissipates into the surroundings. That’s what meant by energy ‘not dying’ but being transformed into other forms. Same as a pond drying up in a drought or a kettle boiling dry. The water is fine, it’s just evaporated, so it exists in a different form, as water vapour, but there’s no pond any more, and no kettle of water you could make tea with.