Jó angolosok! Szerintetek jó? Kijavítanátok?

I'm writing(nincs to)you because I would like (csak szebben hangzik)to thank you for your help

It was really kind of you and we are all grateful for ( to be grateful to somebody FOR something) your help.

A végén kicsit sok a NOW, bár ez nem nyelvtani csak fogalmazási hiba. Javaslat: (...) because she is healthy!

Thanks, Bobbie.

Amúgy jó, nekem tetszik.

Dear Sir,

I am writing to you to thank you for all your help.

We are all very grateful for your kindness. My mother's health has improved in the following few days and we are so happy that she is enjoying good health again.

Sincerely,

Bobbie