Laptop Dies When Unplugged

Hello all, first time here.

Recently inherited this MacBook from my dad who hasn’t used it in a year. The battery does not keep a charge and the laptop can only run on the power adapter. The MagSafe stays a constant orange. I have reset the PRAM and SMC and ran the hardware diagnostics which says everything is normal. Power report is as follows:

Battery Information:

• Model Information:
  • Serial Number: C0142270EFVF90MA5
  • Manufacturer: DP
  • Device Name: bq20z451
  • Pack Lot Code: 0
  • PCB Lot Code: 0
  • Firmware Version: 511
  • Hardware Revision: 000a
  • Cell Revision: 1200
• Charge Information:
  • Charge Remaining (mAh): 839
  • Fully Charged: No
  • Charging: No
  • Full Charge Capacity (mAh): 6018
• Health Information:
  • Cycle Count: 105
  • Condition: Normal
  • Battery Installed: Yes
  • Amperage (mA): 11
  • Voltage (mV): 7395

It seems like the cycle count of 105 is well within its expected lifetime but I suspect the year with no use could have destroyed the battery. Anyways. not sure why there is a small amperage but it says it is not charging at all. I would bring the laptop to the Genius Bar or a service center but few places are open with COVID19 right now.

I’m willing to replace the battery myself if it seems that is the solution.

Thank you in advance for any guidance.