The Mourning of Muharram (also known as the Remembrance of Muharram or Muharram Observances) is a set of rituals associated with mainly Shia Muslims; however, some Muslims from other sects, as well as some non-Muslims, also take part in the remembrance. The commemoration falls in Muharram, the first month of the Islamic calendar. Many of the events associated with the ritual take place in congregation halls known as Hussainia.
Human beings have their own ways to express their feelings of grief and sadness as well to express their feelings of happiness. Islam allows different ways of expression of feelings as far as it does not contradict a clear ruling of Islam. No one can express his happiness by dancing, simply because dancing is forbidden in Islam. No one can express his sadness by drinking beer or alcohol, simply because drinking alcohol or beer is forbidden in Islam.
People whom you mentioned in your question are expressing their feelings of grief by their own way which does not contradict with any Islamic clear rule, and does not have bad effect on the image of Islam.
Allah (SWT) grants people the reward according to their intentions. These people are observing and remembering the tragedy of Karbala. May Allah (SWT) grant them reward according to their intentions.
You must be sure that you and your children will always follow Ahlul Bayt (AS). Don't take any risk in this crucial matter. I advise you to invite him to read few books written by Sunni scholars who became followers of Ahlul Bayt (AS) after researching Sunni and Shia books e.g The I was guided by Dr Samawi Tijani and The Miising Link etc.
After reading such books and being able to ask questions to Shia scholars, he should be able to decide his following Ahlul Bayt (AS).
She is allowed to do so for serving the noble aims of Ahlul Bayt (AS). Men will be allowed to listen as far as her voice does not cause unwanted effect on non Mahram men, otherwise they should avoid listening.
Beating our chest is a sign of mourning and sadness on the tragedies of Ahlul Bayt(AS). It was practiced by early Muslims including Ayisha on her father's death (al-Tabaqaat al-Kubba by Ibn Sa'd, V.2, P.201), and pious believers on the tragedies of Ahlul Bayt (AS).
It is not self violence but expressing our feelings which helps us as well as confirm our love and attachment with the Prophet (SAWA) and his Progeny Ahlul Bayt (AS).
The short answer is, azadari is optional not required, so if you don't want to do it or don't want to be in a place where people are doing it, this is not *religiously* necessary (although, socially, in some places, this may be a challenge).
The longer answer is, bad thoughts and misgivings come from somewhere. Sometimes they arise for good reasons, such as seeing people do wrong or hypocritical things.
Sometimes they arise for bad reasons, such as listening to false ideas (such as some of the baseless criticisms of Shiism in some websites) or self-hatred/embarrassment about one's culture.
So, it doesn't hurt to look into what you are thinking and explore why you are thinking it, and whether it is something that is leading you towards truth and a more enlightened way of being, or not.
Whether or not you choose to make azadari part of your life, it is good to be tolerant towards other people's practices (insofar as they are permissible) and to acknowledge and respect them even if you choose not to do them.
Otherwise if we become intolerant towards how other people live their religion simply because we disagree with them, we will not be any different from those people who go around attacking Shiis for being kuffar because Shiis pray on turbahs and that sort of thing.
Also, regarding azadari, sometimes people become less enthusiastic about azadari as they get older. I guess this is because younger people have more energy and spirit and also things are newer to us when we are younger, then at some point we max out on what we are getting out of azadari, and wish to explore other things. This is of course not true for everyone (I can already imagine the emails of objection flooding my inbox!) but it is true for some people and for most things in life; that is, sometimes things work for us during some life phases and not others.
Religiously speaking, there are also plenty of other things you can focus on that are also meritorious, for instance, if, currently in your life, you feel like you get more out of focusing on reciting the Qur'an or doing charitable work or something else that has value. Of course it is still also meritorious to remember and express sadness for Ahl al-Bayt (A)!
Thank you for your question. In the same way that we mourn departed loved ones out of the love and mercy for them that exists in our hearts, even if they may have been martyred, so too the lovers of Ahl al-Bayt (as) mourn the terrible tragedy that befell them (as).
That certainly does not take away from their reward, rather through God’s Mercy, their tribulation and the softness of our hearts towards them, and the mourning that is a natural consequence, has been validated and made into a worship by God. Crying for the tragedy of Imam Husayn (as) is praiseworthy and has been associated with great rewards in our scriptural literature. It is from here that the tradition of mourning finds its roots.
May you always be successful