Hello and sorry about this little mishap.

Sadly there isn't anything you can do for the leg, but you can make the frog comfortable. It's not an infection so no need for the hospital setup. Provide his original home minus the makeshift hut that calapsed.

Will he accept food from tongs? If so continue feeding him if he will eat. Keep stress as low as possible and try not to hamdle him unless absolutely necessary. Extra supplements will not really change anything.

Protein is what repairs wounds so just feed him and keep a close eye on him. You may still want to seek out a Herp Vet just to be sure all your options are covered.

P.S. You can buy huts already made that do not fall apart, but are not necessary. Fake plants with large broad leaves make excellent cover for them to hide under.

Keep us posted.