Firstly:
We must note that Islam forbids entering upon non-mahram women. The evidence for that is as follows: 

It was narrated from ‘Uqbah ibn ‘Aamir (may Allaah be pleased with him) that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “Beware of entering upon women.” A man from among the Ansaar said, “O Messenger of Allaah, what do you think of the in-law?’ He said, “The in-law is death.” 

(Narrated by al-Bukhaari, 4934; Muslim, 2172) 

The in-law refers to relatives of the husband who are not mahrams for the wife. 

It was narrated that Ibn ‘Abbaas (may Allaah be pleased with him) heard the Prophet (peace and blessings of Allaah be upon him) say: “No man should be alone with a (non-mahram) woman and (a woman) should not travel except with a mahram.” 

(Narrated by al-Bukhaari, 2844; Muslim, 1341). 

Secondly: 

The Shaytaan may make a woman, even if she is old, appear attractive in the eyes of a young man or old man, or vice versa, and may make him gradually fall into immoral actions. There are many stories that illustrate this. 

Thirdly: 

It is better for one of these young men to delegate his wife or sister or daughter, or some of the Muslim sisters, to do this good deed. This is better than a man serving her (the old lady). It is better and more effective for women to deal with women than for men to do so, especially when it comes to matters having to do with rulings that affect women. But if there are women (who can do this), then it is permissible (for a man) to serve her, on condition that he not be alone with her. So one or more other brothers should go with you, and that should also be subject to other shar’i conditions such as hijaab etc., and you should only stay with her for as long as is necessary. 

Fourthly: 

May Allaah reward you greatly for this good deed. We ask Allaah to make us and you and all the Muslims steadfast.  

And Allaah knows best.