Was my husband exploited by the startup?

My husband (20+ years as a Principal Architect) was recruited by a startup to work ~100 hours/month as part-time CTO, with a promise to join full-time after 1.5 years. His employer allowed it because we know the owner personally.

They offered 2% advisory equity over 4 years + a token salary (4% of his real pay). But his work wasn’t “advisory” — he handled architecture, daily team support, coding, vendor coordination, mentoring, everything.

When it was time to bring him on full-time, their investor backed out and they fired the whole team. My husband still stayed for another year, doing full coding for 6 months and maintenance + pitch support for 6 months.

After they finally got funding, he declined the full-time role because of the instability. Then the founder moved the goalposts and said he’d only get 20% of the original 2% if he worked another year part-time. He did that — and now another investor backed out.

Now they’re telling him he must keep advising because he “holds” that 20%.

At this point it feels like they used him for 2+ years of cheap engineering + CTO-level work and gave almost no equity in return. People I spoke to said “advisory equity” was the wrong structure entirely for what he contributed.

Is this normal startup behavior, or did the founder just take advantage of him?