There are examples of this usage, as mentioned by strategies for parents.com:

     Is It Correct to Say “and Myself”?
You should only use “and myself” when your subject is “I” and you include yourself as one of multiple objects. You can only use “myself” when speaking from the first-person point of view, and using “myself” when the subject is not “I” results in an error grammarians call the “untriggered reflexive.”

Here is an example of a grammatically correct sentence that contains “and myself”:

I bought two tickets to the basketball game for William and myself.

The usage of "and myself" here is the same as in the sentence you reference to:

I am reminded of the deeply touching letters, cards and messages which so many of you have sent my wife and myself and I cannot thank you enough for the love and sympathy you have shown our whole family.

Thus, using "myself" this way is correct grammar.

There are examples of this usage, as mentioned in Strategies for Parents.com:

     Is It Correct to Say “and Myself”?
You should only use “and myself” when your subject is “I” and you include yourself as one of multiple objects. You can only use “myself” when speaking from the first-person point of view, and using “myself” when the subject is not “I” results in an error grammarians call the “untriggered reflexive.”

Here is an example of a grammatically correct sentence that contains “and myself”:

I bought two tickets to the basketball game for William and myself.

The usage of "and myself" here is the same as in the sentence you reference to:

I am reminded of the deeply touching letters, cards and messages which so many of you have sent my wife and myself and I cannot thank you enough for the love and sympathy you have shown our whole family.

Thus, using "myself" this way is correct grammar.

There are examples of this usage, as mentioned here:

You should only use “and myself” when your subject is “I” and you include yourself as one of multiple objects. You can only use “myself” when speaking from the first-person point of view, and using “myself” when the subject is not “I” results in an error grammarians call the “untriggered reflexive.”

Here is an example of a grammatically correct sentence that contains “and myself”:

I bought two tickets to the basketball game for William and myself.

The usage of "and myself" here is the same as in the sentence you reference to:

I am reminded of the deeply touching letters, cards and messages which so many of you have sent my wife and myself and I cannot thank you enough for the love and sympathy you have shown our whole family.

Thus, using "myself" this way is correct grammar.

There are examples of this usage, as mentioned by strategies for parents.com:

     Is It Correct to Say “and Myself”?
You should only use “and myself” when your subject is “I” and you include yourself as one of multiple objects. You can only use “myself” when speaking from the first-person point of view, and using “myself” when the subject is not “I” results in an error grammarians call the “untriggered reflexive.”

Here is an example of a grammatically correct sentence that contains “and myself”:

I bought two tickets to the basketball game for William and myself.

The usage of "and myself" here is the same as in the sentence you reference to:

I am reminded of the deeply touching letters, cards and messages which so many of you have sent my wife and myself and I cannot thank you enough for the love and sympathy you have shown our whole family.

Thus, using "myself" this way is correct grammar.