how to edit this sentence?

It's a bit awkward and could use several commas, but it's not wrong.

With commas:

"Once your loved one is ready to move to a lower level of care, the social working will be assisting...."

It's also wordy.

It could be shortened to:

"Once your loved one is ready to move to a lower level of care, the social worker will assist to ensure a smooth transition back to the community."

However, because a lower level of care doesn't automatically mean a return to community dwelling, the sentence probably should read:

"When your loved one is ready, the social worker will help ensure a smooth return to community living."

Hope that helps.

Once your loved ones situation improves, the social worker will see to it that their progress is monitored closely to make a smoother transition to the community.