Tier 2 and Tier 5 Sponsor (COS)

Hello Friends,

One of my friend is currently on Tier-2 (Gen).

He is working for a client, the client is having Tier-5 sponsor license. He is planning to join his client.

Now please one of you clarify the below queries.

can his client provide a COS for Tier-2 Visa? (his client is having only tier-5 license not tier 2)
Or
I know, Tier-2 can't switch to Tier - 5, is there any other option/advice?

Your help is much appreciated.

The only option can be if you are interested to work with your client who holds Tier 5 liecence

He can apply a Tier 2 liecence . Once they hold a Tier 2 liecence

They need to get RLMT done to employ you

I hope this make sense