It is not known whether the sons will contest the will. However, because Lewis left them nothing and a no-contest clause was not included, then a challenge to the will is not a risk to them.
That could turn out to be a mistake, since even losing will contests can end up costing estates a lot of time and money.
If you would like to exclude any children of yours from your estate plan, then it is important that you do so properly.
An estate planning attorney can advise you on creating an estate plan that fits your unique circumstances, which could include avoiding costly legal challenges.
