As said earlier, physical control of the router trumps all.
You are trying to solve a social problem with technological workarounds.
If, indeed, he is blocking your devices at the router....he should not be doing that.
You have 4 basic options:
1. Discussion. "Dude, don't do that"
2. Get and pay for your own connection. Let him suck up the total cost of his.
3. Kick him out
4. You move to a different residence.
Is it only you that he is messing with?