Recently My Father (55) Had A Tumor (4×3×2 Size) Removed

Recently my father (55) had a tumor (4×3×2 size) removed from his left anterior frontal convexity. Tumor was benign and it was in meningioma. It was a grade 1 tumor and the removal was successful as per the surgeons, biopsy had it further confirmed.

The issue now is that his speech and behaviour is affected post surgery. It takes him a lot of time to answer simple day to day questions. He seems to be slightly angry and displays a negative attitude, which is quite unlike him. Day by day the situation is improving, like the speech is getting faster, and he is able to repeat the sentences once said without much effort.

My doubt is how long will it usually take for complete recovey and is there any kind of therapy that we should be looking in to. Thankyou in advance for taking your time to reply.