Hand writing with an electric pen/stylus would be easier to accepted by elders. Alternative way is finger writing on a touch screen or touch pad. However, you may also suggest another method -- voice input. Many Chinese IMEs (input methods) now support voice input, e.g. Sougou Pinyin; QQ Pinyin. Just click the microphone icon on the IME's bar, you will see the voice input interface. It's easy to record your voice and interpret it into text. Here is a step by step tutorial: https://jingyan.baidu.com/article/4ae03de31b67883efe9e6b43.html
Some prerequisites of using voice input:
1. Your verbal Mandarin should be good without too much accent.
2. Internet connection may be needed.
3. Your Windows/Mac device has a pretty good microphone.
These IMEs also support for writing Chinese characters by mouse device if you don't have a touch screen or pad. This is inefficient, but an alternative choice in some cases.