Brief Answer:
Seems to follow bronchitis attack.

Detailed Answer:

Hi,

Though each of the symptom can have it's own cause....quite possible that all of them originate from the bronchitis he was suffering from. Let us think each symptom separately &see how it can be connected to his basic problem of bronchitis.

1.loss of appetite &metallic taste could be due to side effect of antibiotics taken for bronchitis.(which destroyed normal intestinal flora, the lactobacilli)It would be fairly managed by taking B. complex preparation /lactobacillus containing pills (Neutrolin B) over the counter.

2.Tingling in his fourth finger ...
it's a neurogenic symptom, can be due to pressure on supplying nerve at spinal level(cervical spine)/pressure at neck level, due to possible cervical rib there...the pressure being exerted during a strong coughing bout./such pressure can be at elbow joint at ulnar notch on inner side of elbow bone.(while Palm lies open to sky)

This can be relieved by Vitamin B12 supplement and rest .In case no relief, needs to be investigated for cause followed by specific treatment by expert.
3.Dizziness he has seems to follow ..weakness after the bronchitis attack &it's stress /possible high blood pressure he is suffering from as a part of aging/it could follow accompanying throat &sinus involvement causing eustachian tubal block.(managed at home by rest/vapor inhalation ) /His low nourishment during the attack , lack of appetite & low blood pressure can cause it.
Light nourishing food ,vitamin supplements &rest would improve him from such problem .

*While managing him with home care as suggested above... a doctor's consultation is desired to assess him physically along with investigations as per need ... to know the exact cause &then give cause specific treatment.
please consult his family physician for specific advise.

I hope that answers your query. Any follow up query is welcome.
Thanks

---