In Massachusetts there has to be a definitive statement about holding title as joint tenants & to the survivor of them.  Without that specific language the tenancy is held to be a tenancy in common.

If, in this case, "for their joint lives" does equal a joint tenancy  with rights of survivorship as is used in Massachusetts, then Herb would be able to convey his interest as a j/t to his sons or anyone else for that matter.  They, in turn, would be tenants in common with Anne, so at Herb's death the heirs would hold a one-half interest in the property, free of the claims of Anne, except for her remainder interest.    Interesting problem.  Thanks for posting it