I think your advice is great. I would also advise your friend to be the best husband and father he possibly can be. He should show his wife a lot of love and respect and make her feel loved all the time.
And I wouldn't wear the tie no matter what. He needs to put his foot down with the elders because they are putting the cart before the horse. If he doesn't put his foot down on a simple tie, they will be in his life and family matters with every little thing. He needs to be a man and put them in their place. Something to the effect of,
"I'm not baptised and I'm not thinking of getting baptised any time soon until I am 100% sure that this is the Truth. If you want me to continue to come to the meetings, you're going to have to back off about the tie. Period. And if my son doesn't want to wear a tie he doesn't have to, unless you can show me in the bible where it says he should. You also need to respect that I AM THE HEAD OF MY FAMILY -- NOT YOU. If you have any concerns, you are not to go to my wife, but go to me personally. Here is my number.
If you go to my wife, you will be disrespecting MY GOD GIVEN AUTHORITY over my own household and I will not tolerate it. Also, no one is to encourage my son to join the theocratic ministry school, become a publisher, get baptised, etc. My son is too young to make any of these decisions and these decisions will be considered by my wife and myself without any interference from anyone in the congregation. This is as it should be -- unless, of course, you can show me otherwise FROM THE BIBLE. Good day, Brothers."
The elders need to be put in place ASAP.
He should plan fun things on meeting nights. He should start a family bible study and ask probing questions from what he has learned to ensure his family learns to think on their own.
The next time she brings up "apostate" materials he should ask her, "I wonder why your elders would worry about anyone reading material from amongst the millions of ex-JWs who have left, unless of course they are afraid the material is damaging and TRUE. It seems that if the material is false they would have nothing to worry about." And take the excerpt from the Truth book that encourages exactly that. "Honey, did you know that there are more ex-JWs than current JW's? I find that very interesting."