Purchasing and active a (CIS) game and playing on different country , it will work ?

Unless steam checks your ip when you going to login on your country (Israel) the game may not work(well bdl 2 is not even released how should we know).To be honest, its a risky move

As i said below, my suggestion is that they'll buy it from a diffrent account and gift it to you, and i also suggest you'll go to steam support and ask them that question to make sure the money is not wasted.

Bump .. someone tried to do it ?

Avoid CIS tagged games unless you plan to play them in a CIS country. They work based on the IP address location so you would need to use a VPN service in order to play them in Israel. Using a VPN would also violate your steam subscriber agreement and have you account suspended indefinitely if caught.

Not worth the risk, buy region free games.

Just so you know, if someone from different country logs into your Steam account then buy some games, then you start those games in your country you are risking one big fat ban. They can create new account and gift you games, but buying game in one country and playing it in other already caused troubles for few people that I know.

Won't work

wow, since when India is a part of CIS? O_o
Anyway, please note, your account is tied up to one region, once you bought something on it. And it is tied according to the region of you payment method, not to your IP address. Thus, if your family is going to use an Israel Bank card or PayPal account tied to Israel, they should use the Israel prices. They can only use Indian prices, if they recieved a bank card from an Indian Bank. And even if that is the case, you may recieve some problems with steam support, because they can't know, whether you really traveled there, or just used VPN.
Also the games you have named have region restriction in them, so you won't be able to play them in Israel.