Hi there.
I am in need of help / info.

I am playing for 2 years now, i got a storage account were i dont play on it at all, onky literly store my pokes and items. Nothing more
Now my littke brother has started playing for 2 weeks now.
We never had any problens playing together on same ip. Just 2 tablets.
But now as soon as he or i login when the other is already online. He gets kicked out.
We cant play anymore together. Trying to do hitdown together etc.
Can this be fixed?
I need help for this.

nope, if you shared the same IP, only one of you can played at a time, and from what i understand from your post did you let your have your storage account, if so, that against the rules, it will be wise to make another account just for him and dont used that other account again.

No grimreaper.
I got my own account mao1. I got my storage account mao1storage, its realy the only thing i do with it, is store my pokes in it.
No lucky dip, no raffle no fights no bids on the auction. Its dorment. Its also linked to my account so trades are instandly.

And then the account coennie
We have played atleast 2 weeks online at the same time on different tablets, no problem.
But now suddenly when the other comes online, the first ones gets kicked out.

As GrimReaper stated,
you're being kicked off because more than one person was found being online at the same time with the same IP address.

Grim's right. It's because the both of you have the same IP address.
Although it IS a bit strange that you were both able to play on it at the same time for a time despite that. O.o