UngeheuerLich
Legend
Fighting style: you can trade one attack to gain an extra reaction. (Insert details).
Warlord, fighter sub-class
3: use your reaction to help an ally
6: you can take the help action as a bonus action.
10; help action last longer
14: ???
Don't forget for the fighting style:
you can spend your second wind to have an ally regain 1d10+level hp.