It’s usually the likeliness to abscond, the risk of reoffending on bail, a threat to public safety, how likely he is to stay communicative with his local authority, interfering with witnesses etc. There are a number of considerations the judge will have to think about.
If he is released, he will be likely to surrender a surety e.g. his passport. The nature of the crimes charged (whether indictable, triable-either-way, summary etc (from most to least serious)) will be taken into account too. His previous convictions will be considered also.
If his house is currently being searched, I think that would also be a risk to him interfering with the course of justice so perhaps he won’t be granted. Hope this helps!