Firstly the cause for itching and dryness should be ruled out. Sometimes old age too renders the skin dry and may lead to itching. In such cases, the following suggestions might help
Use a mild soap like cetaphil
or hidrate or dove
Apart from using oilatum solution, he should immediately apply a moisturiser just after bathing like venusia or elovera lotion etc
He may continue with fexofenadine
If the problem still persists despite these measures, he may apply steroid
lotion in the concerned areas.
Hope that helps. Take care