ANSWER:

Delaying it this much is not permissible.

Either give it to someone else who is poor or needy immediately or call them and tell them that you have this much amount as zakat for them and it is kept with your mother until she comes in few months time, whether they accept it or send to get it their own way. 

I have to pay my zakat al maal this week. I will give some of it to my uncle’s widow & kids who are poor and sick and live in the countryside in North Africa. However I don’t see them as I live in Europe…my mum is only going there in the summer. Can I give my mum the money now and she will give it to them in July or August?