My partner is blind and can't walk properly. Where can I get a free wheelchair?

Has he spoken with his doctor about getting a wheelchair?

Because being legally blind comes with ALOT of benefits, this is where I would start.

Is your partner a Veteran? If so the VA could provide one.
Your partner's doctor can write an order for one if it is necessary and insurance will cover DME (durable medical equipment)
Often you can find used wheelchairs at resale shops.
Nurses Lending Closets, many villages have them or check your local Senior Center.

Try asking the partner's doctor, social worker, insurance company, local medical equipment bank or local agency on aging or for the blind.

Contact your local area's Agency on Aging for resources. Or try craigslist.org, Nextdoor.com (ISO = In Search Of) or ask their doctor if they can be recommended for one through Medicare or Medicaid.