Dilution of the sort you seem to be describing would expose the founder and investor to a minority oppression lawsuit from OP which could result in monetary damages, and/or the forced sale of all or part of the company at a price determined by the court.

You can't just dilute people without there being any consequences, unless the new shares are being sold at a justifiable price and at an arm's length. The attempts made so far by the founder to push out the OP would color any future dilution, making it harder to justify that dilution in court, even if on the surface it appears legitimate.

If the shares are not sold to a third-party arms-length investor, OP would have to be given the opportunity to participate in the share issuance on a proportional basis. If the founder and investor conspire to issue shares to themselves with the sole purpose of diluting OP, not only would that dilution possibly be reversed in court, but further sanctions could be imposed on the founder and investor as well.