If he wants to invest in more startups, it may work to point out to him how tightly connected the founder community is. He may simply not realize the cost of maltreating you. But an investor suing a startup he invested in is so rare that a story about it could not fail to attract the attention of every other startup in his market.
You're absolutely right about taking money from experienced angels, I'd add always take money from somebody who understands the sector. Seems obvious, I know.