Many multiemployer health plans heavily subsidize the cost of retiree coverage until the retiree is Medicare eligible. This is obviously a huge financial burden.

I have recently heard of certain multiemployer plans that
are conditioning the retiree health care subsidy on one's
active membership in the union. The idea is to eliminate the subsidy to those retirees who are no longer supporting the organizing/lobbying efforts of the union.

I know that qualified retirement plans cannot discriminate against retirees (w/ respect to suspension of benefits) based on his union or non-union status. Is there any similar restriction on
this action by a health fund? Thanks for your time.

I don't see any discrimination here since we would be talking about 2 different classes - union vs. non-union. Employers can have different benefits for different classes. What they can't do is have different benefits for different employees in the same class.

Many unions don't permit a member who retires to retain his membership. How is that handled?