M.K.
Dear E.,
I only have a 18 month old son which I nursed until he was almost 14 months, so I can't say if boys are different than girls. I do think every kid is different and your son just might be on the go more.
I only nursed my son probably 4 times a day at that age. Morning, before naps and night. He ate 3 meals a day too but if he wasn't nursing as much I lighten up on his food. Kids really do know how many calories they need (not like us adults) So if he is getting too much food he won't nurse as much. I would try offering less food, and at that age I didn't really give my son any juice or water really. So if your are offering other liquids you can cut back on that too.
All in all though, go with the flow. I don't think he is totally weaning. My son slowly breastfed less and less as he got older until it was just the night time feed( around 1 year old) which was hard to break he did not want to stop the night feed, I needed to.
My son is very healthy, rarely gets sick, never had a ear infection, is meeting all milestone if not ahead, top of the growth charts. So to me that says he has gotten plenty of nutrition to thrive.
As for the distractions, I would put a his blankey over his head so he couldn't see things and nurse him in his room. You could nurse your son in his room with your daughter there and maybe explain to her you need some quiet time for him to nurse. She could look at books, etc. My son loves to look at books, but I don't know how your daughter is. I think your son will nurse if he is hungry.
Hope that helps,
M.