(Pr 13:22) One who is good will leave an inheritance to sons of sons.
(Pr 19:14) The inheritance from fathers is a house and wealth.
(Ps 34:10) But as for those seeking Jehovah, they will not lack anything good.
(2Co 12:14) for the children ought not to lay up for [their] parents, but the parents for [their] children.
*** w04 9/1 p. 26 What Inheritance Do You Owe Your Children? ***
It is not only natural but also Scriptural for Christian parents to make provisions for their children. The apostle Paul told Christians in his day: “Parents should make provision for their children, not children for their parents.” (2 Corinthians 12:14, The New English Bible)
Seems that they are choosing to lean on Jehovah, so I'd let them.
Otherwise they could get jobs as you mentioned, or sell up and downsize to buy some more time.
Parents or not, their chosen lifestyle should not dictate how you enjoy your own home/family life.
Say you'll help them find jobs if they need extra money, since that's the way it works for everyone in the western world.
Splash.