It would be better if the slogan used by this charity said something like “Winter aid” or “Winter protection”, so that it could apply to blankets, clothes, stoves, etc.
With regard to money that has been collected for a specific purpose, it should only be spent on that specific thing, unless it is too difficult to do so.
For example, we collected money to buy winter blankets for a specific village, and half of the amount was sufficient to buy the blankets, but they also need clothes or heating. In this case there is nothing wrong with spending the left-over money to meet their other needs. But if this was a general appeal, and people are in need of blankets, it is not permissible to spend the money collected in any other way.
So it is not appropriate to spend the money that was collected for blankets on anything else, unless it is well known among the people that “winter blankets” includes all kinds of help in winter. Hence the slogan should be changed to “Winter aid” or something similar.
Shaykh Muhammad ibn ‘Uthaymeen (may Allaah have mercy on him)