He was shunned when he left but over time they've mostly stopped shunning. Since they're trying to get them back. Only odd thing is he can't eat at the table when he visits his father. For the group he was from, Battery power is okay mostly, but they use a lot of solar and generator power to charge batteries. No direct power from generators or solar.
Shunning has changed in recent years among the O and N Orders. It has not changed with the Swartzies and lower groups.
Getting baptized and joining Amish church is not a casual commitment. They view it as a vow, not only to God, but to the church you are joining. So, if you join and then leave, they take Paul's instructions to the church in I Corinthians about wayward, immoral believers and not eating or doing business with such a person and they apply it to someone who decides they don't want to be Amish any longer. This shunning is called being put in the "ban". Other Amish, even those from other churches in some cases, will not speak, eat, or do business with someone put in the ban.
You are correct that the ban isn't what it used to be. In the old days, someone would leave the Old or New Order Amish church, get put in the ban, attend a Mennonite church for a few years while the Amish shunned them, then their pastor would go to the bishop, declare that the banned person was a member in good standing, and ask that the ban be lifted - with mixed results. It depended on the cantankerousness and stubbornness of that particular bishop. Part of the reason for the change is that Mennonite and other pastors started to bluntly instruct Amish bishops that they were misapplying Paul's instructions. Shunning was meant for those members of the church who were living in gross, public sin, not for those who decided to go to a different church. Amish bishops seemed to respond to that criticism over the years and modify when they put someone in the ban and under what circumstances they would take it off. So, today, there is less of it and it is much easier to get it called off.
In the NO and OO, if you do not ever join the church, and you leave, there is no ban. They do not assume any authority over you if you are not a member of the church. If you are a member of the church and leave, they will put you in the ban usually for a while, but if you join another Christian church, they will take it off on request. If you leave and are living in open sin, they will leave the ban on. The goal is to essentially pressure such a one to return to the faith, fellowship of the church, and live within moral boundaries.
In the lower groups, the church does assume authority over young non-members. If a kid leaves their family to live "English", the bishop will instruct the parents to not allow the child back into the house, even for a brief visit, for fear that their "bad example" will lead their brothers and sisters astray. Many a young person has had their father slam the door in their face when they tried to visit their family. The parents have to obey the bishop in this, otherwise, they could be put in the ban. It's very coercive and, therefore, cultish.
In the higher groups, if a former member is in the ban, after a certain amount of time, the bishop would often allow visits, but the banned would have to eat in another room and not with the family.
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Some New, New Order Amish have electricity from the grid, but they have a bunch of rules about what kind of appliances they can have. The OO and NO cannot have grid electricity, but there are various allowances for certain businesses, depending on the type of Amish church. But as a general rule, the OO and NO use solar systems, generators, and batteries for certain limited appliances like pumps, lights, sewing machines, etc. The lower Amish forbid these things.
