Dear friend, welcome to HCM!
Convulasions and headache are strong indicators of significant head injury
Did he bang his head as he fell?
Even though, he needs to be evaluated in ER and scanned if (mostly will) need be.
Head injury and spinal trauma
needs to be looked for.
You should take him to the ER.
Take care and please keep me informed of your progress.
I hope to have answered your query satisfactorily.