Every single one of us has a home parish based on where we live. We can attend Mass anywhere, but, only one is canonically ours.
Determine what is your home parish.
Every boy I’ve ever met is hyperactive at age 6 and every 3 year old is going to follow the lead of their brother. Every parent in that church has been there, done that.
At age 6, your son will this fall begin his preparation (in most US Parishes it is 2 years long) for First Communion. This is the very most important reason to get established at your home parish.
The Catechists who do FHC prep have a heart for squirmy, talkative, bouncy, anxious kids.
The best news is, every time the go to Mass they learn a little bit more. When parents stay calm, kids read that.
Parents here will have great advice, I suggest meeting with the Faith Formation/Rel Ed director now to talk about Sacramental Prep this fall.
Start at home with 5 minutes of quiet time in the evening. No TV, no screens for anyone, everyone is together and they are free to read a book, draw a picture, for 5 minutes. Simply no chatting or making noise. Mom and dad both set the example and read a book or pray a silent decade of the rosary or just sit and be quiet.
Each week, extend it by one minute.
Every parish tends to sing the same hymns over the weeks. Learn the hymns, sing them at home, learn the prayer responses. You can find your parish’s mass settings on line so they learn the tune of the Sanctus or the Gloria.
These are things that the boys can do during Mass - sing out and say the responses - that break it up into not an hour of “sit still and don’t move!” to “sit still for a few minutes, then we get to sing/stand/pray”. Mass keeps us moving!
Mass is made up of little bits of quiet then we get to move and do something else.
Watching the altar servers is also a cool thing because after FHC your oldest can BE a server!
Sit up front where they can see all of the action on the Altar.
Reward good Mass with a donut or ice cream.
Remember, your boys are being boys. If they need to go out in the lobby/gathering space and do 10 pushups/jumping jacks then go back in, let them burn off some energy that way.