My father has owned a barbershop business in the same location for 49 years. The lease expires next month and the landlord wants him and his sublesse to vacate. The sublesse spent thousands of dollars setting up the jewelry business just 5 years ago and now faces loseing his livlihood as well as my dad.

So what is the question? Your dad should have known 5 years ago, 2 year ago 1 year ago, that the lease was expiring and that they needed to get a new lease or start looking for a new location.

This is not unexpected in very long term, and/or of course a large increase in cost if they did stay.

So they need to look for another locatoin as close to this one as they can, advertise a move and go on in business. I am in my third location but stayed within a couple miles of each other in my main business.

So have they found a new place to move to yet. They do not own the property, they just lease, and at the end of the lease they either have to sign a new rental agreement or be moved out.

Any "improvements" that are part of the building stay with the building unless permission is given to take them.

Your dad can't leave his shop to go looking, but you can, and the jeweler can help somewhat too. I take it the landlord just announced this on May 1, otherwise you would have asked sooner. Hardly seems fair, but it's still legal. Maybe you can reason and negotiate for another month or two to find a place and move. If the neighborhood has improved maybe a higher rent is in order? Do you have any idea why the space is suddenly wanted?
Negotiate, negotiate.