Nevertheless after comma is good style?

Alan Cochrane, a competent writer, used one in the Telegraph:

• He took a bit of persuading but he did it, nevertheless.

This looks perfectly acceptable to me.

Note that this sense of nevertheless is synonymous with 'anyway' (though the comma would usually be dropped here). It is a 'sentence adverb' or what I'd call a 'pragmatic marker: class concessive/cancellative' (see David Bell; Science Direct: Journal of Pragmatics) usage.

From Collins Cobuild:> nevertheless [adverb]

You use nevertheless when saying something that contrasts with what has just been said. [formal]

• His father, though ill-equipped for the project, had nevertheless tried his best.

Notice that the positioning of even a clause-modifying 'adverb' is quite fluid.

...................

But here:

• He took a bit of persuading; nevertheless, he did it.

a comma would not be heavy-duty enough. Two sentences are needed, or (as they will be semantically closely related) the equivalent use of a semicolon.

'Nevertheless' in this role is classed as a 'sentence connector' by some authorities (eg Collins) and as a 'conjunctive adverb' by others; it behaves differently from say 'but'.

Grammarly [modified] contains:

4. Use Semicolons With Conjunctive Adverbs

When you have a conjunctive adverb linking two independent clauses, you should use a semicolon [before it]. Common conjunctive adverbs include moreover, nevertheless, however, otherwise, therefore, then, finally, likewise, and consequently.

• I needed to go for a walk and get some fresh air; also, I needed to buy milk.
• Reports of the damage caused by the hurricane were greatly exaggerated; indeed, the storm was not a “hurricane” at all.
• The students had been advised against walking alone at night; however, Cathy decided walking wasn’t dangerous if it was early in the evening.
• I’m not all that fond of the colors of tiger lilies; moreover, they don’t smell very good.

These words sometimes show up in other parts of a sentence; therefore, the semicolon rule only applies if it helps the conjunctive adverb join two independent clauses. This conjunctive adverb rule is similar to the conjunction rule. In both cases, check that the two ideas are independent clauses that could stand on their own as sentences. If so, then the semicolon is the correct choice.