Mars
sita,
Mars has to do with our "actions" and, when frustrated or challenged frequently can lead to our becoming "angry". Pluto has to do with "power" and "death" while Uranus has to do with "rebellion". So when Mars aspects Pluto stressfully (conjunction, square, or opposition), there are "angry power" issues which could lead to violent death. When Mars aspects Uranus stressfully, there are "angry rebellion" issues such as violent overthrows of authority or rebelling against anyone who symbolizes authority.
Saturn, however, has to do with "restriction". So when Mars aspects Saturn stressfully there is commonly a challenge in taking action. This creates a growing "frustration" in the person which could be "touched off" by a stressful aspect of Mars to Pluto or Uranus either in the birth chart or by transit.
In the chart example you give, there is Pluto opposite Mars in one person's chart, indicating the possibility of violent, angry power issues. The other person's Saturn is opposing Mars, indicates that they may be seen as somehow "frustrating" the Pluto opposite Mars person's ability to take action. This could cause a very violent reaction in the Pluto opposite Mars person.
If your dad has a history of violence, this could be a serious issue. I would suggest being very careful about being seen as "too restrictive" around him. If your dad does not have a history of violence, then most likely he has learned some postiive way to use his Pluto opposite Mars energy. But it would still be wise to be careful about "restricting" him.
Explaining,
Tim