Cool find, and I’m afraid he is going to crow about it!
Looks to be a sceat with a ‘female centaur [note the pair of boobs] surrounded by palm fronds’ obverse. This probably isn’t your exact coin, but it’s a similar design type:
View attachment 2065254
That one is Series S, Type 47 from between 710-760 AD with a reverse design ‘whorl of four stylised wolf heads, their beaded tongues meeting in the centre’. Diameter 12mm, weight 1.01g. Your reverse is too corroded for me to comment further but probably ‘Crusader’ will be able to type it more precisely.