the head gasket is bad on my moms 95 ford windstar is it worth fixing or should i do a engine swap

If your positive it is a bad head gasket and not a cracked head yes do the head gasket.

yeah my mom took it to shop and they said thats whats wrong this is 3rd or 4th head gasket needed replacement

Assuming 3.8?

Ford has a re-engineered head gasket set, as well as a reinforced timing cover gasket thats prone to fail.. A H/gasket change is a good time to do both head/timing if it hasn't been done already.. If this has had 'repeat' head gasket failures, could be the quality of parts used, or service.. Torque to yield head bolts 'must' be replaced during a gasket replacement or an early failure can/will occur.. Heads checked for flat, and/or machined.. If the upgrade gaskets weren't used, new headbolts, heads/deck checked for flat or even damage from 'gasket removal' (some shops use abrasive discs) then the best service life you can expect is only as good as the original set, or less.. What shop did the previous work??

Somethings wrong with the 'quality' of repair, or it would have to be driven pretty hard or get hot to need 4 sets of head gaskets...Even three!!