Is there a way that i can buy EA Access with my microsoft account using gift card?

No. Microsoft account balances are not set up to work for third party subscriptions. You would need a prepaid EA Access card.

EA access is only working with special ea access gift cards which afaik are not released yet. Usual microsoft gift cards are NOT working!

Currency from gift cards can only be used to purchase games and other content. It is not set up to work with a recurring subscription so it cannot be used to buy gold and it does not work with third party subscriptions so it won't work for EA Access. You
would need to purchase subscriptions via credit card/PayPal or buying a prepaid gold or EA Access card.

How can I access the gift card? In my order history when I purchased the gift card it says i got "miscellaneous credit" of $1.25 added to my microsoft account, not a gift card.

Unfortunately, you can't sign into your friends account, as his account would still be an UK based account, even if you signed into it from the USA.

Additionally, allowing a third party to access ones account is against the Microsoft Terms of Use, and your friend would risk a suspension on his account if he were to let you access his account.

Since Microsoft can't do currency conversion, your friend can not use the currency code you have in any way.

If you really wish to gift him a currency gift card, you'd better go to
https://www.amazon.co.uk (make sure it's .co.uk, not .com) and buy him a gift card in British Pounds.

You can then use the US Dollar gift card for yourself or another friend in the US.