Di Maria fear for family after break-in attempt
It was reported last weekend that the Argentina international was having dinner when intruders attempted to smash a patio door, but fled empty-handed.
Di Maria and his family are said to have relocated to a hotel following that incident and Van Gaal expressed concerns over the former Real Madrid man's state of mind ahead of the FA Cup fourth round replay against Cambridge United on Tuesday.
The 26-year-old requested to start the clash with the League Two side and Van Gaal was impressed with his performance following a difficult few days.
He said: "I believe in the total human being principle, so his environment is also important. He was worried about his wife and child.
"I spoke with him and he wanted to play against Cambridge United and I played him. I have decided in the past that I will never play a player in those circumstances, because of the total human being principle.
"But with him I had the feeling that I had to give him a chance to play and I was happy that I let him play. He played very well. And, of course, I have to decide on Sunday [at West Ham] again, but when you have seen his performance against Cambridge, I don't think I have any doubt."
Di Maria was replaced by Ander Herrera in that routine victory at Old Trafford and Van Gaal has urged the Spaniard to raise his game in order to secure a place in United's starting line-up.
He said: "I have to compare him with people like [Wayne] Rooney and [Juan] Mata, for example, so that's difficult, they are all at a high level - he has to improve,
"But he's a great guy, he's a very great professional also, so that's not the problem - his problem is he has to compete with high-level players and Rooney is also the captain so he has a privilege.
"So then the other places are the place of the position in this system that we are playing now with a number 10 and that's Mata and that's Di Maria. That's difficult to compete against but he did already know that at the moment that he signed for Manchester United.
"When you sign for a top club like he did he knows that he is had to fight but he is fighting.
"He is coming back, there were a lot of weeks he was down but now he is coming back."