Hello and good morning.
This shows that the implant has failed and the fracture is not stable anymore, and therefore it is unlikely to unite, even with bed rest. Basically the fracture is not going to heal properly at this stage unless it is stabilised. Bed rest will not help to stabilise this unstable fracture.
Next Steps
I understand that it may be distressing, but the best option right now is to do a revision surgery. The original plate and screws will be removed and a new implant, preferably a rod inside the bone, will be needed.
You can visit the original surgeon again and ask him about the option of a repeat surgery, or you can take a second opinion with a senior orthopaedic surgeon.
Health Tips
You may be apprehensive and afraid of a repeat surgery, but please know that this is the best option to get him walking and healthy again. There have been significant number of studies proving that in most cases with hip fractures, bed rest is actually more harmful than a repeat surgery for the patient.
Take care, and get well soon.