TS seem to forget it is his and future wife's wedding, not his parents or parent-in-law to be's wedding.

He should discuss with his gf first, then present a united front to parents-in-law.

If gf is not on board with him, ie rowing on the same boat in the same direction even at this point.

Really should consider say bye bye now and not later.

I find especially worrying that TS says this "little girl" will listen to everything that her mum says.

Just imagine, later TS having sex with his mum-in-law via the "little gf" wife because mum-in-law says must liddis not liddat. AMBOI.