Hi Dr I Need Your Help My Mother Is 61

hi dr
I need your help
my mother is 61 years old had breast cancer breast and she had her chemotherapy for 8 doses 4 ac and 4 taxol then radiotherapy on the left side after mastectomy and axillary clearance
then she had some sideffects mainly peripheral neuropathy
she started Neurontin 300 mg 3 times daily for about 3 months now
then she had repeated svt
dr said may be because of Neurontin then she suddenly stopped Neurontin and at the same time she started concor 2.5 daily
after 3 days she experienced suddenly arthralgia and confusion and symptoms of depression and hallocinations
could this happens due to Neurontin shut down
or concor ( bisoprolol ) side effects
or gabapentin bisoprolol drug interaction ?
n b she had brain ct scan after confusion syptoms 12 hours and it was free of brain metastasis or embolus
or infarction or heamorrage
please help me ASAP to understand and if so tell me how to withdrow gabapentin or bisoprolol safely